24. hvac

HEATING & AIR CONDITIONING

TABLE OF CONTENTS

page page

HEATING & AIR CONDITIONINGDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1DIAGNOSIS AND TESTING . . . . . . . . . . . . . . . . . . 2

A/C PERFORMANCE . . . . . . . . . . . . . . . . . . . . . 2HEATER PERFORMANCE . . . . . . . . . . . . . . . . . 6

STANDARD PROCEDURE . . . . . . . . . . . . . . . . . . . 7DIODE REPLACEMENT . . . . . . . . . . . . . . . . . . . 7

SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . 7CONTROLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9DISTRIBUTION . . . . . . . . . . . . . . . . . . . . . . . . . . 36PLUMBING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

HEATING & AIRCONDITIONING

DESCRIPTION - COOLING SYSTEMREQUIREMENTS

To maintain the performance level of the heating-air conditioning system, the engine cooling systemmust be properly maintained. The use of a bugscreen is not recommended. Any obstructions in frontof the radiator or condenser will reduce the perfor-mance of the air conditioning and engine cooling sys-tems.

The engine cooling system includes the heater coreand the heater hoses. Refer to Cooling for more infor-mation before opening, or attempting any service tothe engine cooling system.

DESCRIPTION - HEATER AND AIRCONDITIONER

A manual temperature control type heating-airconditioning system is standard factory-installedequipment on this model. An electronically controlledAutomatic Zone Control (AZC) type heating-air con-ditioning system is an available factory-installedoption.

All vehicles are equipped with a common HVAChousing assembly (Fig. 1). The system combines airconditioning, heating, and ventilating capabilities ina single unit housing mounted under the instrumentpanel.

DESCRIPTION - REFRIGERANT SYSTEMSERVICE PORT

The two refrigerant system service ports are usedto charge, recover/recycle, evacuate, and test the airconditioning refrigerant system. Unique service portcoupler sizes are used on the R-134a system toensure that the refrigerant system is not accidentallycontaminated by the use of the wrong refrigerant(R-12), or refrigerant system service equipment.

OPERATION - HEATER AND AIR CONDITIONEROutside fresh air enters the vehicle through the

cowl top opening at the base of the windshield, andpasses through a plenum chamber to the HVAC sys-tem blower housing. Air flow velocity can then beadjusted with the blower motor speed selector switchon the a/c heater control panel. The air intake open-ings must be kept free of snow, ice, leaves, and otherobstructions for the HVAC system to receive a suffi-cient volume of outside air.

It is also important to keep the air intake openingsclear of debris because leaf particles and other debristhat is small enough to pass through the cowl plenumscreen can accumulate within the HVAC housing. Theclosed, warm, damp and dark environment createdwithin the HVAC housing is ideal for the growth ofcertain molds, mildews and other fungi. Any accumu-

Fig. 1 COMMON BLEND-AIR HVAC SYSTEM1 - BLEND DOOR2 - EVAPORATOR CORE3 - BLOWER4 - PANEL/DEFROST DOOR5 - HEAT/DEFROST DOOR6 - HEATER CORE7 - RECIRCULATION DOOR

WJ HEATING & AIR CONDITIONING 24 - 1

lation of decaying plant matter provides an additionalfood source for fungal spores, which enter the housingwith the fresh air. Excess debris, as well as objection-able odors created by decaying plant matter andgrowing fungi can be discharged into the passengercompartment during HVAC system operation.

Both the manual and AZC heater and air condi-tioner are blend-air type systems. In a blend-air sys-tem, a blend door controls the amount ofunconditioned air (or cooled air from the evaporator)that is allowed to flow through, or around, the heatercore. A temperature control knob on the a/c heatercontrol panel determines the discharge air tempera-ture by energizing the blend door actuator, whichoperates the blend door. This allows an almost imme-diate control of the output air temperature of the sys-tem. The AZC system will have separate blend doorsand temperature controls for each front seat occu-pant.

The mode control knob on the a/c heater controlpanel is used to direct the conditioned air to theselected system outlets. On manual temperature con-trol systems, the mode control knob switches enginevacuum to control the mode doors, which are oper-ated by vacuum actuators. On AZC systems, themode control knob switches electrical current to con-trol the mode doors, which are operated by electronicactuators.

The outside air intake can be shut off on manualtemperature control systems by selecting the Recircu-lation Mode with the mode control knob. The outsideair intake can be shut off on Automatic Zone Control(AZC) type system by pushing the RecirculationMode button. This will operate the recirculation doorthat closes off the outside fresh air intake and recir-culates the air that is already inside the vehicle.

The air conditioner for all models is designed forthe use of non-CFC, R-134a refrigerant. The air con-ditioning system has an evaporator to cool and dehu-midify the incoming air prior to blending it with theheated air. This air conditioning system uses a vari-able orifice tube in the liquid line near the condenseroutlet tube to meter refrigerant flow to the evapora-tor coil. To maintain minimum evaporator tempera-ture and prevent evaporator freezing, the a/c lowpressure switch on the accumulator cycles the com-pressor clutch. (Refer to 24 - HEATING & AIR CON-DITIONING/CONTROLS/A/C LOW PRESSURESWITCH - OPERATION)

OPERATION - REFRIGERANT SYSTEM SERVICEPORT

The high pressure service port is located on thedischarge line near the condenser. The low pressureservice port is located on the suction line near theevaporator at the rear of the engine compartment.

Each of the service ports has a threaded plasticprotective cap installed over it from the factory. Afterservicing the refrigerant system, always reinstallboth of the service port caps.

DIAGNOSIS AND TESTING - A/CPERFORMANCE

The air conditioning system is designed to providethe passenger compartment with low temperatureand low specific humidity air. The evaporator, locatedin the HVAC housing on the dash panel below theinstrument panel, is cooled to temperatures near thefreezing point. As warm damp air passes through thecooled evaporator, the air transfers its heat to therefrigerant in the evaporator and the moisture in theair condenses on the evaporator fins. During periodsof high heat and humidity, an air conditioning sys-tem will be more effective in the Recirculation Mode.With the system in the Recirculation Mode, only airfrom the passenger compartment passes through theevaporator. As the passenger compartment air dehu-midifies, the air conditioning system performancelevels improve.

Humidity has an important bearing on the temper-ature of the air delivered to the interior of the vehi-cle. It is important to understand the effect thathumidity has on the performance of the air condition-ing system. When humidity is high, the evaporatorhas to perform a double duty. It must lower the airtemperature, and it must lower the temperature ofthe moisture in the air that condenses on the evapo-rator fins. Condensing the moisture in the air trans-fers heat energy into the evaporator fins and tubing.This reduces the amount of heat the evaporator canabsorb from the air. High humidity greatly reducesthe ability of the evaporator to lower the temperatureof the air.

However, evaporator capacity used to reduce theamount of moisture in the air is not wasted. Wring-ing some of the moisture out of the air entering thevehicle adds to the comfort of the passengers.Although, an owner may expect too much from theirair conditioning system on humid days. A perfor-mance test is the best way to determine whether thesystem is performing up to standard. This test alsoprovides valuable clues as to the possible cause oftrouble with the air conditioning system.

If the vehicle has the optional Automatic Zone Con-trol (AZC) system, and has intermittent operationalproblems or fault codes, be certain that the wire har-ness connectors on the HVAC housing are properlyseated (Fig. 2). To check this condition, unplug thetwo wire harness connector halves, then plug them inagain.

24 - 2 HEATING & AIR CONDITIONING WJ

HEATING & AIR CONDITIONING (Continued)

Before performing the following procedure, (Referto 24 - HEATING & AIR CONDITIONING/PLUMB-ING - CAUTION) (Refer to 24 - HEATING & AIRCONDITIONING/PLUMBING - WARNING). The airtemperature in the test room and in the vehicle mustbe a minimum of 21° C (70° F) for this test.

(1) Connect a tachometer and a manifold gaugeset.

(2) If the vehicle has the standard manual temper-ature control, set the A/C Heater mode control switchknob in the Panel position, the temperature controlknob in the full cool (Recirculation Mode) position,the A/C button in the On position, and the blowermotor switch knob in the highest speed position. Ifthe vehicle has the optional AZC, set the A/C Heatermode control switch knob in the Panel position, thetemperature control knob in the full cool position, theA/C and Recirc buttons in the On position, and theblower motor switch knob in the highest (manual)speed position.

(3) Start the engine and hold the idle at 1,300 rpmwith the compressor clutch engaged.

(4) The engine should be at operating temperature.The doors and windows must be open.

(5) Insert a thermometer in the driver side centerA/C (panel) outlet. Operate the engine for five min-utes.

(6) The compressor clutch may cycle, dependingupon the ambient temperature and humidity. If theclutch cycles, unplug the low pressure switch wireharness connector from the switch located on theaccumulator (Fig. 3). Place a jumper wire across the

terminals of the low pressure switch wire harnessconnector.

(7) With the compressor clutch engaged, record thedischarge air temperature and the compressor dis-charge pressure.

(8) Compare the discharge air temperature to thePerformance Temperature and Pressure chart. If thedischarge air temperature is high, (Refer to 24 -HEATING & AIR CONDITIONING/PLUMBING -DIAGNOSIS AND TESTING - REFRIGERANT SYS-TEM LEAKS) and (Refer to 24 - HEATING & AIRCONDITIONING/PLUMBING - STANDARD PRO-CEDURE - REFRIGERANT SYSTEM CHARGE).

Fig. 2 WIRE HARNESS CONNECTORS1 - INSTRUMENT PANEL2 - HVAC HOUSING3 - INSTRUMENT PANEL WIRE HARNESS4 - BLOWER MOTOR

Fig. 3 ACCUMULATOR AND LOW PRESSURESWITCH

1 - SERVICE PORT2 - LOW PRESSURE SWITCH3 - ACCUMULATOR4 - SUPPORT BRACKET



Performance Temperature and Pressure

Ambient AirTemperature andHumidity

21° C(70° F @ 80%

humidity)

27° C(80° F @ 80%

humidity)

32° C(90° F @ 80%

humidity)

38° C(100° F @

50% humidity)

43° C110° F @ 20%

humidity)

Air Temperature atCenter Panel Outlet

0 to 9° C(32 to 48° F)

1 to 12° C(33 to 54° F)

3 to 17° C(37 to 63° F)

6 to 18° C(43 to 65° F)

10 to 18° C(50 to 65° F)

Evaporator InletPressure at ChargePort

151 to 262 kPa(22 to 38 psi)

221 to 248kPa

(32 to 36 psi)

262 to 296kPa

(38 to 43 psi)

303 kPa(44 psi)

310 kPa(45 psi)

Compressor DischargePressure

900 to 1380kPa

(130 to 200psi)

1380 to 2070kPa

(200 to 300psi)

1720 to 2140kPa

(250 to 310psi)

1860 to 2140kPa

(270 to 310psi)

2070 to 2550kPa

(300 to 370 psi)

Note: The discharge air temperatures will be lower if the humidity is less than the percentages shown.

(9) Compare the compressor discharge pressure tothe Performance Temperature and Pressure chart. If

the compressor discharge pressure is high, see thePressure Diagnosis chart.

Pressure Diagnosis

Condition Possible Causes Correction

Rapid compressor clutchcycling (ten or more cyclesper minute).

1. Low refrigerant systemcharge.

1. See Plumbing/Diagnosis and Testing -Refrigerant System Leaks in this group. Test therefrigerant system for leaks. Repair, evacuate andcharge the refrigerant system, if required.

Equal pressures, but thecompressor clutch does notengage.

1. No refrigerant in therefrigerant system.


2. Faulty fuse. 2. Check the fuses in the Power DistributionCenter and the junction block. Repair the shortedcircuit or component and replace the fuses, ifrequired.

3. Faulty a/c compressorclutch coil.

3. See A/C Compressor/Diagnosis and Testing -Compressor Clutch Coil in this group. Test thecompressor clutch coil and replace, if required.

4. Faulty compressor clutchrelay.

4. See A/C Compressor Clutch Relay/Diagnosisand Testing - Compressor Clutch Relay in thisgroup. Test the compressor clutch relay and relaycircuits. Repair the circuits or replace the relay, ifrequired.

5. Improperly installed orfaulty a/c low pressureswitch.

5. See A/C Low Pressure Switch/Diagnosis andTesting in this group. Test the a/c low pressureswitch and tighten or replace, if required.

6. Faulty a/c high pressureswitch.

6. See A/C High Pressure Switch/Diagnosis andTesting in this group. Test the a/c high pressureswitch and replace, if required.

7. Faulty Powertrain ControlModule (PCM).

7. Refer to the proper Diagnostic Proceduresmanual for testing of the PCM. Test the PCM andreplace, if required.



Pressure Diagnosis


Normal pressures, but A/CPerformance Test airtemperatures at center paneloutlet are too high.

1. Excessive refrigerant oil insystem.

1. See Refrigerant Oil/Standard Procedure -Refrigerant Oil Level in this group. Recover therefrigerant from the refrigerant system andinspect the refrigerant oil content. Restore therefrigerant oil to the proper level, if required.

2. Blend door inoperative orsealing improperly.

2. See Blend Door in this group. Inspect theblend door for proper operation and sealing andcorrect, if required.

3. Blend door actuator faultyor inoperative.

3. Perform blend door actuator diagnosis, replaceif faulty.

The low side pressure isnormal or slightly low, andthe high side pressure is toolow.

1. Low refrigerant systemcharge.


2. Refrigerant flow throughthe accumulator is restricted.

2. See Accumulator in this group. Replace therestricted accumulator, if required.

3. Refrigerant flow throughthe evaporator coil isrestricted.

3. See A/C Evaporator in this group. Replace therestricted evaporator coil, if required.

4. Faulty compressor. 4. See A/C Compressor in this group. Replacethe compressor, if required.

The low side pressure isnormal or slightly high, andthe high side pressure is toohigh.

1. Condenser air flowrestricted.

1. Check the condenser for damaged fins, foreignobjects obstructing air flow through the condenserfins, and missing or improperly installed air seals.Refer to Cooling for more information on air seals.Clean, repair, or replace components as required.

2. Inoperative cooling fan. 2. Refer to Cooling for more information. Test thecooling fan and replace, if required.

3. Refrigerant systemovercharged.

3. See Plumbing/Standard Procedure - RefrigerantSystem Charge in this group. Recover therefrigerant from the refrigerant system. Charge therefrigerant system to the proper level, if required.

4. Air in the refrigerantsystem.


5. Engine overheating. 5. Refer to Cooling for more information. Test thecooling system and repair, if required.

The low side pressure is toohigh, and the high sidepressure is too low.

1. Accessory drive beltslipping.

1. Refer to Cooling for more information. Inspectthe accessory drive belt condition and tension.Tighten or replace the accessory drive belt, ifrequired.

2. A/C fixed orifice tube notinstalled.

2. See A/C Fixed Orifice Tube in this group.Replace the liquid line if a/c fixed orifice ismissing. See Liquid Line in this group.

3. Faulty compressor. 3. See A/C Compressor in this group. Replacethe compressor, if required.



Pressure Diagnosis


The low side pressure is toolow, and the high sidepressure is too high.

1. Restricted refrigerant flowthrough the refrigerant lines.

1. See Liquid, Suction, and Discharge Line in thisgroup. Inspect the refrigerant lines for kinks, tightbends or improper routing. Correct the routing orreplace the refrigerant line, if required.

2. Restricted refrigerant flowthrough the a/c fixed orificetube.

2. See A/C Fixed Orifice Tube in this group.Replace the liquid line if restricted. See LiquidLine in this group.

3. Restricted refrigerant flowthrough the condenser.

3. See A/C Condenser in this group. Replace therestricted condenser, if required.

DIAGNOSIS AND TESTING - HEATERPERFORMANCE

Before performing the following tests, refer to Cool-ing for the procedures to check the radiator coolantlevel, serpentine drive belt tension, radiator air flowand the radiator fan operation. Also be certain thatthe accessory vacuum supply line is connected at theengine intake manifold for the manual temperaturecontrol system.

MAXIMUM HEATER OUTPUTEngine coolant is delivered to the heater core

through two heater hoses. With the engine idling atnormal operating temperature, set the temperaturecontrol knob in the full hot position, the mode controlswitch knob in the floor heat position, and the blowermotor switch knob in the highest speed position.Using a test thermometer, check the temperature ofthe air being discharged at the HVAC housing flooroutlets. Compare the test thermometer reading to theTemperature Reference chart.

Temperature Reference

Ambient Air Temperature15.5° C(60° F)

21.1° C(70° F)

26.6° C(80° F)

32.2° C(90° F)

Minimum Air Temperature atFloor Outlet

62.2° C(144° F)

63.8° C(147° F)

65.5° C(150° F)

67.2° C(153° F)

If the floor outlet air temperature is too low, referto Cooling to check the engine coolant temperaturespecifications. Both of the heater hoses should be hotto the touch. The coolant return heater hose shouldbe slightly cooler than the coolant supply heaterhose. If the return hose is much cooler than the sup-ply hose, locate and repair the engine coolant flowobstruction in the cooling system. Refer to Coolingfor the procedures.

OBSTRUCTED COOLANT FLOWPossible locations or causes of obstructed coolant

flow:• Pinched or kinked heater hoses.• Improper heater hose routing.• Plugged heater hoses or supply and return ports

at the cooling system connections.• A plugged heater core.If proper coolant flow through the cooling system is

verified, and heater outlet air temperature is stilllow, a mechanical problem may exist.

MECHANICAL PROBLEMSPossible locations or causes of insufficient heat:• An obstructed cowl air intake.• Obstructed heater system outlets.• A blend door not functioning properly.

TEMPERATURE CONTROLIf the heater outlet air temperature cannot be

adjusted with the temperature control knob(s) on theA/C Heater control panel, the following could requireservice:

• The A/C heater control.• The blend door actuator(s).• The wire harness circuits for the A/C heater con-

trol or the blend door actuator(s).• The blend door(s).• Improper engine coolant temperature.



STANDARD PROCEDURE - DIODEREPLACEMENT

(1) Disconnect and islolate the negative batterycable.

(2) Locate the diode in the harness, and removethe protective covering.

(3) Remove the diode from the harness, pay atten-tion to the current flow direction (Fig. 4).

(4) Remove the insulation from the wires in theharness. Only remove enough insulation to solder inthe new diode.

(5) Install the new diode in the harness, makingsure current flow is correct. If necessary refer to theappropriate wiring diagram for current flow.

(6) Solder the connection together using rosin coretype solder only. Do not use acid core solder.

(7) Tape the diode to the harness using electricaltape making, sure the diode is completely sealedfrom the elements.

(8) Re-connect the battery, and test affected sys-tems.

SPECIFICATIONS

A/C APPLICATION TABLE

Item Description Notes

VEHICLE WJ - GrandCherokee

SYSTEM R134a w/ fixedorifice tube

COMPRESSOR Nippondenso10PA17

ND-8 PAG oil

Item Description Notes

Freeze–upControl

A/C LowPressureSwitch

accumulatormounted

Low psi Control opens < 22 psi- resets > 34-38psi

High psi Control opens >450-490 psi -resets <270-330 psi

line mounted

CONTROLHEAD

manual type manual controls

Automatic ZoneControl (AZC)

Automatic ZoneControl (AZC)with dualinfrared sensing

Mode Doors vacuumactuators(manual)

electric actuator(AZC)

Blend Door electric actuator (manual andAZC)

Blend Door(passenger)

electric actuator (AZC only)

RecirculationDoor

vacuumactuator(manual)

electric actuator(AZC)

Blower Motor hardwired tocontrol head

resistor block(manual),blower controller(AZC)

COOLING FAN Hybrid -viscousclutch/electric

PCM output

CLUTCH

Control relay PCM controlled

Draw 2.0-3.9 amps@ 12 V

6 0.5V@ 70° F

Gap 0.0169-0.0319

DRB IIIT

Reads TPS, RPM, A/Cswitch

Actuators clutch relay

Fig. 4 DIODE IDENTIFICATION1 - CURRENT FLOW2 - BAND AROUND DIODE INDICATES CURRENT FLOW3 - DIODE AS SHOWN IN THE DIAGRAMS



TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

DESCRIPTION N·m Ft. Lbs. In. Lbs.

A/C COMPRESSORSHAFT BOLT

13 - 115

A/C COMPRESOR LINEMANIFOLD FASTENERS

4.0L/4.7L25.4 - 225

A/C COMPRESOR LINEMANIFOLD FASTENERS

3.1L DIESEL22 - 200

A/C COMPRESSOR TOENGINE BLOCK BOLTS -

4.0L/4.7L

45-65 35-50 -

A/C COMPRESSOR TOENGINE BLOCK BOLTS -

3.1L DIESEL

41 30 -

A/C COMPRESSOR REARBRACE BOLTS - 4.0L

40-55 30-40 -

A/C COMPRESSOR REARBRACE BOLTS - 4.7L

35-45 25-35 -

A/C CONDENSER TOREFRIG. LINEFASTENERS

28 - 250

A/C EVAPORATOR LINEFASTENERS

28 - 250

ACCUMULATORRETAINING BAND

(4.0L/4.7L)

12 - 105

ACCUMULATORRETAINING BAND (3.1L

DIESEL)

5 - 45

BLOWER MOTORSCREWS

2.2 - 20

DOOR ACTUATORSCREWS

2.2 - 20

HVAC HOUSING SCREWS 2.2 - 20

HVAC HOUSING TO DASHPANEL NUTS (ENGINE

COMP. SIDE)

7 - 60

HVAC HOUSING TO DASHPANEL NUTS

(PASSENGER COMP.SIDE)

4.5 - 40

SUCTION LINE TOACCUMULATOR FITTING

28 - 250


SPECIFICATIONS (Continued)

CONTROLS

TABLE OF CONTENTS

page page

CONTROLSDIAGNOSIS AND TESTING . . . . . . . . . . . . . . . . . 10

VACUUM SYSTEM . . . . . . . . . . . . . . . . . . . . . . 10A/C COMPRESSOR CLUTCH

DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . 13OPERATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13DIAGNOSIS AND TESTING . . . . . . . . . . . . . . . . . 13

COMPRESSOR CLUTCH COIL. . . . . . . . . . . . . 13STANDARD PROCEDURE . . . . . . . . . . . . . . . . . . 13

COMPRESSOR CLUTCH BREAK-IN. . . . . . . . . 13REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14INSTALLATION. . . . . . . . . . . . . . . . . . . . . . . . . . . 15

A/C COMPRESSOR CLUTCH RELAYDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . 16OPERATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16DIAGNOSIS AND TESTING . . . . . . . . . . . . . . . . . 16

A/C COMPRESSOR CLUTCH RELAY . . . . . . . . 16REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17INSTALLATION. . . . . . . . . . . . . . . . . . . . . . . . . . . 17

A/C HEATER CONTROLDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . 17OPERATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17DIAGNOSIS AND TESTING . . . . . . . . . . . . . . . . . 18

AUTOMATIC ZONE CONTROL SYSTEM . . . . . 18REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24INSTALLATION. . . . . . . . . . . . . . . . . . . . . . . . . . . 25

A/C HIGH PRESSURE SWITCHDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . 25OPERATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25DIAGNOSIS AND TESTING . . . . . . . . . . . . . . . . . 25

A/C HIGH PRESSURE SWITCH . . . . . . . . . . . . 25REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25INSTALLATION. . . . . . . . . . . . . . . . . . . . . . . . . . . 25

A/C LOW PRESSURE SWITCHDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . 26OPERATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26DIAGNOSIS AND TESTING . . . . . . . . . . . . . . . . . 26

A/C LOW PRESSURE SWITCH . . . . . . . . . . . . 26REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26INSTALLATION. . . . . . . . . . . . . . . . . . . . . . . . . . . 26

BLOWER MOTOR CONTROLLERDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

OPERATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27INSTALLATION. . . . . . . . . . . . . . . . . . . . . . . . . . . 27

BLOWER MOTOR RESISTOR BLOCKDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . 28OPERATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28DIAGNOSIS AND TESTING . . . . . . . . . . . . . . . . . 28

BLOWER MOTOR RESISTOR BLOCK . . . . . . . 28REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28INSTALLATION. . . . . . . . . . . . . . . . . . . . . . . . . . . 28

BLOWER MOTOR SWITCHDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . 29OPERATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29DIAGNOSIS AND TESTING . . . . . . . . . . . . . . . . . 29

BLOWER MOTOR SWITCH-MANUALTEMPERATURE CONTROL SYSTEM . . . . . . . . 29

REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29IN-CAR TEMPERATURE SENSOR

DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . 30OPERATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

BLEND DOOR ACTUATORDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . 30REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30INSTALLATION. . . . . . . . . . . . . . . . . . . . . . . . . . . 31

MODE DOOR ACTUATORDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . 31REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31INSTALLATION. . . . . . . . . . . . . . . . . . . . . . . . . . . 32

RECIRCULATION DOOR ACTUATORDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . 33REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33INSTALLATION. . . . . . . . . . . . . . . . . . . . . . . . . . . 34

VACUUM CHECK VALVEDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . 34OPERATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35INSTALLATION. . . . . . . . . . . . . . . . . . . . . . . . . . . 35

VACUUM RESERVOIRDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . 35OPERATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35INSTALLATION. . . . . . . . . . . . . . . . . . . . . . . . . . . 35

WJ CONTROLS 24 - 9

CONTROLS

DIAGNOSIS AND TESTING - VACUUM SYSTEMVacuum control is used to operate the mode doors

in the standard equipment manual temperature con-trol system HVAC housing. Testing of the A/C Heatermode control switch operation will determine if thevacuum and electrical controls are functioning. How-ever, it is possible that a vacuum control system thatoperates perfectly at engine idle (high engine vac-uum) may not function properly at high enginespeeds or loads (low engine vacuum). This can becaused by leaks in the vacuum system, or a faultyvacuum check valve.

A vacuum system test will help to identify thesource of poor vacuum system performance or vac-uum system leaks. Before starting this test, stop theengine and make certain that the problem isn’t a dis-connected vacuum supply tube at the engine intakemanifold vacuum tap or the vacuum reservoir.

Use an adjustable vacuum test set (Special ToolC-3707-B) and a suitable vacuum pump to test theHVAC vacuum control system. With a finger placedover the end of the vacuum test hose probe (Fig. 1),adjust the bleed valve on the test set gauge to obtaina vacuum of exactly 27 kPa (8 in. Hg.). Release andblock the end of the probe several times to verify thatthe vacuum reading returns to the exact 27 kPa (8in. Hg.) setting. Otherwise, a false reading will beobtained during testing.

VACUUM CHECK VALVES(1) Remove the vacuum check valve to be tested.

The valves are located in the (black) vacuum supplytubes at either the engine intake manifold vacuumtap, or on the bottom of the HVAC unit behind thepassenger front floor duct.

(2) Connect the test set vacuum supply hose to theA/C Heater control side of the valve. When connectedto this side of the check valve, no vacuum shouldpass and the test set gauge should return to the 27kPa (8 in. Hg.) setting. If OK, go to Step 3. If not OK,replace the faulty valve.

(3) Connect the test set vacuum supply hose to theengine vacuum side of the valve. When connected tothis side of the check valve, vacuum should flow

through the valve without restriction. If not OK,replace the faulty valve.

A/C HEATER CONTROL(1) Connect the test set vacuum probe to the

HVAC vacuum supply (black) tube in the engine com-partment. Position the test set gauge so that it canbe viewed from the passenger compartment.

(2) Place the A/C Heater mode control switch knobin each mode position, one position at a time, andpause after each selection. The test set gauge shouldreturn to the 27 kPa (8 in. Hg.) setting shortly aftereach selection is made. If not OK, a component orvacuum line in the vacuum circuit of the selectedmode has a leak. See the procedure in Locating Vac-uum Leaks.

CAUTION: Do not use lubricant on the switch portsor in the holes in the plug, as lubricant will ruin thevacuum valve in the switch. A drop of clean waterin the connector plug holes will help the connectorslide onto the switch ports.

Fig. 1 ADJUST VACUUM TEST BLEED VALVE -TYPICAL

1 - VACUUM PUMP TOOL C-42892 - VACUUM TEST SET C-37073 - BLEED VALVE4 - PROBE

24 - 10 CONTROLS WJ

LOCATING VACUUM LEAKS

WARNING: ON VEHICLES EQUIPPED WITH AIR-BAGS, DISABLE THE AIRBAG SYSTEM BEFOREATTEMPTING ANY STEERING WHEEL, STEERINGCOLUMN, OR INSTRUMENT PANEL COMPONENTDIAGNOSIS OR SERVICE. DISCONNECT AND ISO-LATE THE BATTERY NEGATIVE (GROUND) CABLE,THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-TEM CAPACITOR TO DISCHARGE BEFORE PER-FORMING FURTHER DIAGNOSIS OR SERVICE. THISIS THE ONLY SURE WAY TO DISABLE THE AIRBAGSYSTEM. FAILURE TO TAKE THE PROPER PRE-CAUTIONS COULD RESULT IN AN ACCIDENTALAIRBAG DEPLOYMENT AND POSSIBLE PERSONALINJURY.

(1) Disconnect the vacuum harness connector fromthe back of the A/C Heater mode control switch onthe control panel.

(2) Connect the test set vacuum hose probe to eachport in the vacuum harness connector, one at a time,and pause after each connection (Fig. 2). The test setgauge should return to the 27 kPa (8 in. Hg.) settingshortly after each connection is made. If OK, replacethe faulty mode control switch. If not OK, go to Step3.

(3) Determine the vacuum line color of the vacuumcircuit that is leaking. To determine the vacuum linecolors, refer to the Vacuum Circuits chart (Fig. 3).

(4) Disconnect and plug the vacuum line from thecomponent (fitting, actuator, valve, switch, or reser-voir) on the other end of the leaking circuit. Instru-ment panel disassembly or removal may be necessaryto gain access to some components.

(5) Connect the test set hose or probe to the openend of the leaking circuit. The test set gauge shouldreturn to the 27 kPa (8 in. Hg.) setting shortly aftereach connection is made. If OK, replace the faultydisconnected component. If not OK, go to Step 6.

(6) To locate a leak in a vacuum line, leave oneend of the line plugged and connect the test set hoseor probe to the other end. Run your fingers slowlyalong the line while watching the test set gauge. Thevacuum reading will fluctuate when your fingers con-tact the source of the leak. To repair the vacuumline, cut out the leaking section of the line. Then,insert the loose ends of the line into a suitable lengthof 3 millimeter (1/8-inch) inside diameter rubberhose.

Fig. 2 VACUUM CIRCUIT TEST

WJ CONTROLS 24 - 11

CONTROLS (Continued)

Fig. 3 VACUUM CIRCUITS

24 - 12 CONTROLS WJ

A/C COMPRESSOR CLUTCH (Continued)

A/C COMPRESSOR CLUTCH

DESCRIPTIONThe compressor clutch assembly consists of a sta-

tionary electromagnetic coil, a hub bearing and pul-ley assembly, and a clutch plate (Fig. 4). Theelectromagnetic coil unit and the hub bearing andpulley assembly are each retained on the nose of thecompressor front housing with snap rings. The clutchplate is keyed to the compressor shaft and securedwith a bolt.

OPERATIONThe compressor clutch components provide the

means to engage and disengage the compressor fromthe engine serpentine accessory drive belt. When theclutch coil is energized, it magnetically draws theclutch into contact with the pulley and drives thecompressor shaft. When the coil is not energized, thepulley freewheels on the clutch hub bearing, which ispart of the pulley. The compressor clutch and coil arethe only serviced parts on the compressor.

The compressor clutch engagement is controlled byseveral components: the a/c switch on the a/c heatercontrol panel, the Automatic Zone Control (AZC) con-trol module (if the vehicle is so equipped), the a/c lowpressure switch, the a/c high pressure switch, the a/ccompressor clutch relay, and the Powertrain ControlModule (PCM). The PCM may delay compressorclutch engagement for up to thirty seconds. Refer toElectronic Control Modules for more information onthe PCM controls.

DIAGNOSIS AND TESTING - COMPRESSORCLUTCH COIL

For circuit descriptions and diagrams, refer to theappropriate wiring diagrams. The battery must befully-charged before performing the following tests.Refer to Battery for more information.

(1) Connect an ammeter (0 to 10 ampere scale) inseries with the clutch coil terminal. Use a voltmeter(0 to 20 volt scale) with clip-type leads for measuringthe voltage across the battery and the compressorclutch coil.

(2) With the a/c heater mode control switch in anya/c mode, the a/c heater control a/c switch in the ONposition, and the blower motor switch in the lowestspeed position, start the engine and run it at normalidle.

(3) The compressor clutch coil voltage should readwithin 0.2 volts of the battery voltage. If there isvoltage at the clutch coil, but the reading is notwithin 0.2 volts of the battery voltage, test the clutchcoil feed circuit for excessive voltage drop and repairas required. If there is no voltage reading at theclutch coil, use a DRBIIIt scan tool and the appro-priate diagnostic information for testing of the com-pressor clutch circuit. The following componentsmust be checked and repaired as required before youcan complete testing of the clutch coil:

• Fuses in the junction block and the Power Dis-tribution Center (PDC)

• A/C heater mode control switch• A/C compressor clutch relay• A/C high pressure switch• A/C low pressure switch• Powertrain Control Module (PCM)(4) The compressor clutch coil is acceptable if the

current draw measured at the clutch coil is 2.0 to 3.9amperes with the electrical system voltage at 11.5 to12.5 volts. This should only be checked with the workarea temperature at 21° C (70° F). If system voltageis more than 12.5 volts, add electrical loads by turn-ing on electrical accessories until the system voltagedrops below 12.5 volts.

(a) If the clutch coil current reading is fouramperes or more, the coil is shorted and should bereplaced.

(b) If the clutch coil current reading is zero, thecoil is open and should be replaced.

STANDARD PROCEDURE - COMPRESSORCLUTCH BREAK-IN

After a new compressor clutch has been installed,cycle the compressor clutch approximately twentytimes (five seconds on, then five seconds off). Duringthis procedure, set the A/C Heater control in theRecirculation Mode, the A/C button in the on posi-tion, the blower motor switch in the highest speed

Fig. 4 COMPRESSOR CLUTCH - TYPICAL1 - CLUTCH PLATE2 - SHAFT KEY3 - PULLEY4 - COIL5 - CLUTCH SHIMS6 - SNAP RING7 - SNAP RING

WJ CONTROLS 24 - 13

position, and the engine speed at 1500 to 2000 rpm.This procedure (burnishing) will seat the opposingfriction surfaces and provide a higher compressorclutch torque capability.

REMOVALThe refrigerant system can remain fully-charged

during compressor clutch, pulley, or coil replacement.The compressor clutch can be serviced in the vehicle.

(1) Disconnect and isolate the battery negativecable.

(2) Remove the serpentine drive belt. Refer toCooling for the procedures.

(3) Remove the bolt that secures the compressorclutch to the compressor shaft (Fig. 5). A band-typeoil filter wrench may be used to secure the clutchduring bolt removal.

(4) Tap the clutch plate with a plastic mallet torelease it from the splines on the compressor shaft.Remove the clutch plate and shim(s) from the com-pressor shaft (Fig. 6).

CAUTION: Do not pry between the clutch plateassembly and the pulley to remove it from the com-pressor shaft. Prying may damage the clutch plateassembly.

(5) Remove the external snap ring that secures thecompressor clutch pulley to the nose of the compres-sor front housing with snap ring pliers (Special ToolC-4574) and slide the pulley assembly off of the com-pressor (Fig. 7).

(6) Remove the screw and retainer from the clutchcoil lead wire harness on the compressor front hous-ing.

(7) Remove the external snap ring that secures thecompressor clutch coil to the nose of the compressorfront housing with snap ring pliers and slide the coilassembly off of the compressor (Fig. 8).

INSPECTIONExamine the friction surfaces of the clutch pulley

and the clutch plate for wear. The pulley and plate

Fig. 5 COMPRESSOR SHAFT BOLT1 - COMPRESSOR CLUTCH PLATE2 - COMPRESSOR SHAFT BOLT

Fig. 6 CLUTCH PLATE AND SHIM(S)1 - COMPRESSOR SHAFT2 - CLUTCH PLATE3 - CLUTCH PLATE SHIM

Fig. 7 PULLEY SNAP RING1 - SNAP RING

24 - 14 CONTROLS WJ


should be replaced if there is excessive wear or scor-ing.

If the friction surfaces are oily, inspect the shaftand nose area of the compressor for refrigerant oil.Remove the felt wick from around the shaft insidethe nose of the compressor front housing. If the feltis saturated with refrigerant oil, the compressorshaft seal is leaking and the compressor must bereplaced.

Check the clutch pulley bearing for roughness orexcessive leakage of grease. Replace the bearing, ifrequired.

INSTALLATION(1) Align the dowel pin on the back of the clutch

field coil with the hole in the compressor front hous-ing and press the field coil into place over the nose ofthe compressor.

(2) Install the clutch coil lead wire harness retain-ing clip on the compressor front housing and tightenthe retaining screw.

(3) Install the clutch field coil and snap ring withsnap ring pliers (Special Tool C-4574). The bevel sideof the snap ring must be facing outward. Also, botheyelets of the snap ring must be to the right or left ofthe pin on the compressor. Press in on the snap ringto be certain that it is properly seated in the groove.

CAUTION: If the snap ring is not fully seated in thegroove it will vibrate out, resulting in a clutch fail-ure and severe damage to the front housing of thecompressor.

(4) Install the pulley assembly onto the compres-sor. If necessary, place a block of wood on the frictionsurface and tap gently with a hammer (Fig. 9).

CAUTION: Do not mar the pulley friction surface.

(5) Install the pulley assembly retaining snap ring(bevel side outward) with snap ring pliers (SpecialTool C-4574). Press in on the snap ring to be certainthat it is properly seated in the groove.

(6) If the original clutch plate assembly and pulleyassembly are to be reused, the old shim(s) can beused. If not, place a stack of shim(s) equal to the oldshim(s) on the shaft against the shoulder.

(7) Install the clutch plate assembly onto theshaft.

(8) With the clutch plate assembly tight againstthe shim(s), measure the air gap between the clutchplate and the pulley face with feeler gauges. The airgap should be between 0.35 to 0.65 millimeter (0.014to 0.026 inch). If the proper air gap is not obtained,add or subtract shims as needed until the desired airgap is obtained.

Fig. 8 CLUTCH COIL SNAP RING1 - SNAP RING PLIERS2 - CLUTCH COIL3 - SNAP RING4 - COMPRESSOR

Fig. 9 PULLEY ASSEMBLY INSTALL1 - PULLEY ASSEMBLY2 - WOOD BLOCK

WJ CONTROLS 24 - 15


(9) Install the compressor shaft bolt. Tighten thebolt to 13 N·m (115 in. lbs.).

NOTE: The shims may compress after tighteningthe shaft bolt. Check the air gap in four or moreplaces to verify the air gap is still correct. Spin thepulley before performing a final check of the airgap.

(10) To complete the installation, (Refer to 24 -HEATING & AIR CONDITIONING/PLUMBING/A/CCOMPRESSOR - INSTALLATION)

A/C COMPRESSOR CLUTCHRELAY

DESCRIPTIONThe compressor clutch relay is a International

Standards Organization (ISO) micro-relay. The termi-nal designations and functions are the same as a con-ventional ISO relay. However, the micro-relayterminal orientation (footprint) is different, the cur-rent capacity is lower, and the relay case dimensionsare smaller than those of the conventional ISO relay.

OPERATIONThe compressor clutch relay is a electromechanical

device that switches battery current to the compres-sor clutch coil when the Powertrain Control Module(PCM) grounds the coil side of the relay. The PCMresponds to inputs from the a/c compressor switch onthe a/c heater control panel, the Automatic Zone Con-trol (AZC) control module (if the vehicle is soequipped), the a/c low pressure switch, and the a/chigh pressure switch. (Refer to 24 - HEATING & AIRCONDITIONING/CONTROLS/A/C COMPRESSORCLUTCH RELAY - DIAGNOSIS AND TESTING)

The compressor clutch relay is located in the PowerDistribution Center (PDC) in the engine compart-ment. Refer to the PDC label for relay identificationand location.

The compressor clutch relay cannot be repairedand, if faulty or damaged, it must be replaced.

DIAGNOSIS AND TESTING - A/C COMPRESSORCLUTCH RELAY

For circuit descriptions and diagrams, refer to theappropriate wiring information.

The compressor clutch relay (Fig. 10) is located inthe Power Distribution Center (PDC). Refer to thePDC label for relay identification and location.Remove the relay from the PDC to perform the fol-lowing tests:

(1) A relay in the de-energized position shouldhave continuity between terminals 87A and 30, and

no continuity between terminals 87 and 30. If OK, goto Step 2. If not OK, replace the faulty relay.

(2) Resistance between terminals 85 and 86 (elec-tromagnet) should be 75 6 5 ohms. If OK, go to Step3. If not OK, replace the faulty relay.

(3) Connect a battery to terminals 85 and 86.There should now be continuity between terminals30 and 87, and no continuity between terminals 87Aand 30. If OK, see the Relay Circuit Test procedurein this group. If not OK, replace the faulty relay.

RELAY CIRCUIT TESTFor circuit descriptions and diagrams, refer to the

appropriate wiring information..(1) The relay common feed terminal cavity (30) is

connected to fused battery feed. There should be bat-tery voltage at the cavity for relay terminal 30 at alltimes. If OK, go to Step 2. If not OK, repair the opencircuit to the fuse in the PDC as required.

(2) The relay normally closed terminal (87A) is notused in this application. Go to Step 3.

(3) The relay normally open terminal cavity (87) isconnected to the compressor clutch coil. There shouldbe continuity between this cavity and the A/C com-pressor clutch relay output circuit cavity of the com-pressor clutch coil wire harness connector. If OK, goto Step 4. If not OK, repair the open circuit asrequired.

(4) The relay coil battery terminal (86) is con-nected to the fused ignition switch output (run/start)circuit. There should be battery voltage at the cavityfor relay terminal 86 with the ignition switch in theOn position. If OK, go to Step 5. If not OK, repair theopen circuit to the fuse in the junction block asrequired.

Fig. 10 A/C COMPRESSOR CLUTCH RELAY30 - COMMON FEED85 - COIL GROUND86 - COIL BATTERY87 - NORMALLY OPEN87A - NORMALLY CLOSED

24 - 16 CONTROLS WJ


(5) The coil ground terminal cavity (85) is switchedto ground through the Powertrain Control Module(PCM). There should be continuity between this cav-ity and the A/C compressor clutch relay control cir-cuit cavity of the PCM wire harness connector C(gray) at all times. If not OK, repair the open circuitas required.

REMOVAL(1) Disconnect and isolate the battery negative

cable.(2) Remove the cover from the Power Distribution

Center (PDC) (Fig. 11).

(3) Refer to the label on the PDC for compressorclutch relay identification and location.

(4) Unplug the compressor clutch relay from thePDC.

INSTALLATION(1) Install the compressor clutch relay by aligning

the relay terminals with the cavities in the PDC andpushing the relay firmly into place.

(2) Install the PDC cover.(3) Connect the battery negative cable.(4) Test the relay operation.

A/C HEATER CONTROL

DESCRIPTIONThe manual temperature control HVAC system

uses a combination of electrical, and vacuum con-

trols. The Automatic Zone Control (AZC) HVAC sys-tem uses only electrical controls. These controlsprovide the vehicle operator with a number of settingoptions to help control the climate and comfortwithin the vehicle. Refer to the owner’s manual inthe vehicle glove box for more information on thesuggested operation and use of these controls.

Both a/c heater control panels are located on theinstrument panel inboard of the steering column andbelow the radio (Fig. 12). Both control panels containrotary-type temperature control knob(s), a rotary-type mode control switch knob, a rotary-type blowermotor speed switch knob and an air conditioningcompressor push button switch. The rear windowdefogger push button switch is also located on a/cheater control panel. The AZC control panel also fea-tures a recirculation push button switch and a vac-uum fluorescent display area.

OPERATIONThe AZC control module uses infrared sensing

technology to control occupant comfort levels, not theactual passenger compartment air temperature. Dualinfrared sensors mounted in the face of the controlunit independently measure the surface temperatureto maintain customer-perceived comfort temperatureunder changing conditions. Dual Zone temperaturecontrol provides wide side-to-side variation in comforttemperature to exceed the needs of either front seatoccupant. This sensing system replaces interior airtemperature and solar sensors used to approximatedirect sensing control through complex control pro-grams.

Fig. 11 POWER DISTRIBUTION CENTER (PDC)1 - TRANSMISSION CONTROL MODULE (TCM)2 - NEGATIVE CABLE3 - POSITIVE CABLE4 - POWER DISTRIBUTION CENTER (PDC)

Fig. 12 A/C HEATER CONTROL PANELS

WJ CONTROLS 24 - 17

A/C COMPRESSOR CLUTCH RELAY (Continued)

Both the manual A/C Heater control panel and theAZC control panel are serviced only as completeunits and cannot be repaired. If faulty or damaged,the entire control panel unit must be replaced.

DIAGNOSIS AND TESTING - AUTOMATIC ZONECONTROL SYSTEM

The Automatic Zone Control (AZC) control modulehas a system self-diagnostic mode which continuouslymonitors various parameters during normal systemoperation. If a system fault is detected, a current andhistorical fault is recorded. When the current fault iscleared, the historical fault remains until reset (man-ually or automatically). Both the current and histor-ical fault codes can be accessed through either thefront panel, or over the Programmable Communica-tions Interface (PCI) bus using a DRBIIIt scan tool,and the appropriate diagnostic information.

The AZC control module is capable of three differ-ent types of self-diagnostic tests, as follows:

• Fault Code Tests• Input Circuit Tests• Output Circuit/Actuator TestsThe information that follows describes:• How to read the self-diagnostic display• How to enter the AZC control module self-diag-

nostic test mode• How to select the self-diagnostic test types• How to perform the different tests

ENTERING THE AZC SELF-DIAGNOSTIC MODETo enter the AZC self-diagnostic mode, perform the

following:(1) Depress the a/c and recirc buttons at the same

time and hold. Rotate the left temperature controlknob clockwise (CW) one detent.

(2) If you continue to keep the a/c and recirc but-tons depressed, the AZC control module will performa Segment Test of the Vacuum Fluorescent (VF) dis-play. In the Segment Test you should see all of thedisplay segments illuminate as long as both buttonsare held. If a display segment fails to illuminate, thevacuum fluorescent display is faulty and the a/cheater control must be replaced.

(3) After viewing the Segment Test, release theA/C and Recirc buttons and the display will clearmomentarily. If a 0 is displayed, then no faultsare set in the system. Should there be any faults,either 9current9 or 9historical9, all fault codes will bedisplayed in ascending numerical sequence (note noeffort is made to display fault codes in chronologicalorder). Each fault code is displayed for one secondbefore the next code is displayed. Once all fault codeshave been displayed, the system will then repeat thefault code numbers. This will continue until the leftside set temperature control is moved at least onedetent position in the CW direction or the ignition isturned 9OFF9.

FAULT CODE TESTSFault codes are two-digit numbers that identify a

circuit that is malfunctioning. There are two differ-ent kinds of fault codes.

• Current Fault Codes - Current means thefault is present right now. There are two types of cur-rent faults: input faults, and system faults.

• Historical Fault Codes - Historical or storedmeans that the fault occurred previously, but is notpresent right now. A majority of historical fault codesare caused by intermittent wire harness or wire har-ness connector problems.

24 - 18 CONTROLS WJ

A/C HEATER CONTROL (Continued)

CURRENT FAULT CODES

Input faults 01 = IR thermister circuit open

02 = IR thermister circuit shorted

03 = Fan pot shorted

04 = Fan pot open

05 = Mode pot shorted

06 = Mode pot open

07 = IR sensor delta too large

08 = Reserved

09 = Reserved

10 = One of four motor drivers has drive 9A9 shorted to ground

11 = Engine air intake temperature Buss message missing

12 = Country code Buss message missing

System Faults 13 = Mode motor not responding

14 = AI (Recirc) motor not responding

15 = Left temperature door not responding

16 = Right temperature door not responding

17 = Mode door travel range too small

18 = Mode door travel range too large

19 = AI (Recirc) door travel too small

20 = AI (Recirc) door travel too large

21 = Left temperature door travel too small

22 = Left temperature door travel too large

23 = Right temperature door travel too small

24 = Right temperature door travel too large

25 = Calibration check sum error

26 = Engine coolant temp bus message missing

27 = Vehicle speed bus message missing

28 = Engine RPM bus message missing

29 = OAT bus message missing

30 = Display intensity bus message missing

31 = VIN number bus message missing

32 = Raw OAT bus message missing

WJ CONTROLS 24 - 19


HISTORICAL FAULT CODES

Input faults 33 = IR thermister circuit was open

34 = IR thermister circuit was shorted

35 = Fan pot was shorted

36 = Fan pot was open

37 = Mode pot was shorted

38 = Mode pot was open

39 = IR sensor delta was too large

40 = Reserved

41 = Reserved

42 = One of four motor drivers had drive 9A9 shorted to ground

43 = Engine air intake temperature Buss message missing

44 = Country code Buss message missing

System Faults 45 = Mode motor was not responding

46 = AI (Recirc) motor was not responding

47 = Left temperature door was not responding

48 = Right temperature door was not responding

49 = Mode door travel range too small

50 = Mode door travel range too large

51 = AI (Recirc) door travel range too small

52 = AI (Recirc) door travel range too large

53 = Left temperature door travel too small

54 = Left temperature door travel too large

55 = Right temperature door travel too small

56 = Right temperature door travel too large

57 = Calibration check sum error

58 = Engine coolant temp bus message missing

59 = Vehicle speed bus message missing

60 = Engine RPM bus message missing

61 = OAT bus message missing

62 = Display intensity bus message missing

63 = VIN number bus message missing

64 = Raw OAT bus message was missing

65 = Reserved

66 = Reserved

67 = Reserved

NOTE: A battery disconnect will erase all faultsstored in Random Access Memory (RAM) of theAZC control module. It is recommended that allfaults be recorded before they are erased.

RETRIEVING FAULT CODES(1) To begin the fault code tests, depress the A/C

and Recirc buttons at the same time and rotate the

left temperature control knob clockwise (CW) onedetent, then release the push-button.

(2) If there are no fault codes, the “00” dis-play value will remain in the VF window. Shouldthere be any codes, each will be displayed for onesecond in ascending numerical sequence (note: noeffort is made to display faults in the order theyoccurred). The left side set temperature display will

24 - 20 CONTROLS WJ


be blanked and the right side set temperature dis-play will indicate current and historical codes (8 his-torical max) presently active. Once all codes havebeen displayed, the system will repeat the fault codenumbers. This will continue until the left side settemperature control is moved at least one detentposition in either direction, by pressing both the A/Cand Recirc buttons at the same time, or the ignitionis turned off. Record all of the fault codes, then seethe Current and Historical Fault Code charts for thedescriptions.

CLEARING FAULT CODESCurrent faults cannot be electronically cleared.

Repair must be made to the system to eliminate thefault causing code. Historical fault codes can becleared manually, or automatically. To clear a histor-ical fault manually, depress and hold either the A/Cor Recirc button for at least three seconds while thedisplay is in the fault code mode of operation. Histor-ical fault codes are cleared automatically when thecorresponding current fault code has been cleared,and has remained cleared for a number of ignitioncycles. The faults have been cleared when two hori-zontal bars appear in the Test Selector display.

EXITING SELF-DIAGNOSTIC MODE The self-diagnostic modecan be exited by pressing both the A/C and Recirc buttonsat the same time, or turning off the ignition.

MONITOR CURRENT PARAMETERSWhile in the display fault code mode of operation,

current system parameters can also be monitoredand/or forced. Rotating the left side set temperaturecontrol clockwise will increase the pointer numberwhile rotating the control counter clockwise willdecrease the pointer number. Rotating the right settemperature control will have no impact on pointervalue or the value of the parameter being monitored.Once the desired pointer number has been selected,pressing either the AC or Recirc buttons will displaythe current value of the selected parameter. Theright side set temperature display is only capa-ble of displaying only values ranging from 0 to99, the left side set temperature display is usedfor values greater than 99. If the value is lessthan 99, the left side set temperature displayremains blanked. While a parameter is being over-ridden, the system will continue to function normallyexcept for the parameter which is being manuallycontrolled.

For values < 0, the 9G9 segment in the left side settemperature Most Significant Digit (MSD)(or left-most number in the pair) will be used to indicate anegative number. For values between -01 to -99 theLeast Significant Digit (LSD)(or right-most numberof the pair) in the left side set temperature will

remain blank. System control of parameter being dis-played can be overridden by rotating the right settemperature control in either direction. Rotating theright temperature control in the CW direction, theselected parameter value is overridden and incre-mented beginning at the value which was being dis-played. Rotating the right temperature control in theCCW direction, the selected parameter value is over-ridden and decremented beginning at the valuewhich was being displayed. The rate at which incre-menting and decrement occurs is one unit value perset temperature detent position.

HVAC SYSTEM POINTER

PointerNumber

DESCRIPTION ValueDisplayed

01 A/C Enable 0 or 1

0 =disabled1 =enabled

02 Final fan PWM duty cycle 0 to 255

While the value of this pointeris being displayed, turning theright set temperature controleither direction will manuallycontrol the value. CW =increase; CCW = decrease

03 Left NPRG * 0 to 255

* NPRG equals a calculated number based on outsideand in-vehicle conditions. This value is used by theAZC to position the Mode motor, Air Inlet motor, and

control blower motor speed.


04 Right NPRG 0 to 255


WJ CONTROLS 24 - 21


HVAC SYSTEM POINTER

05 Avg NPRG 0 TO255


06 Primary control side 0 or 1

0 = left 1= right

07 EE Check sum (calculated) 0 to 255

08 Target intensity (in % ON time) 0 to 255


09 Not Used 0 to 0

10 Not Used 0 to 0

11 Right NINC * 0 to 255

* NINC equals a calculated number based on the IRsensor and IR thermistor values used to calculate the

NPRG.


12 Left NINC 0 to 255


13 Right NMIX * 0 to 255

* NMIX equals a calculated number based on outsideand in-vehicle conditions used by the AZC to position

the Temperature motors.


HVAC SYSTEM POINTER

14 Left NMIX 0 to 255

While the value of this pointeris being displayed, turning theright set temperature controleither direction will manuallycontrol the value. CW =increase; CW = decrease

15 Not Used 0 to 0

16 Not Used 0 to 0

17 Reserved

18 Reserved

19 Reserved

MODE VALUE POINTER

PointerNumber


20 mode range in delta counts 0 to9999

21 Current mode position (incounts)

0 to9999

22 mode target position in ratio 0 to 255


23 mode target position in counts 0 to9999

24 Not Used 0 to 0

25 number of valve moves sincelast index

0 to9999

26 Not Used 0 to 0

27 Not Used 0 to 0

28 Not Used 0 to 0

29 mode motor state 0 to 5

0 = in position, 1 = movingtoward panel, 2 = movingtoward defrost, 3 = searchingrange, 4 = stalled movingtoward panel, 5 = stalledmoving toward defrost

24 - 22 CONTROLS WJ


LEFT SIDE TEMPERATURE POINTER

PointerNumber


30 Left side temp range in deltacounts

0 to9999

31 Current left side temp position(in counts)

0 to9999

32 Left side temp target position(in ratio)

0 to 255


33 Left side temp target in counts 0 to9999

34 Not used 0 to 0


0 to9999

36 Not used 0 to 0

37 Not used 0 to 0

38 Not used 0 to 0

39 Left side temp motor state 0 to 5


RIGHT SIDE TEMPERATURE POINTER

PointerNumber


40 Right side temp range in deltacounts

0 to9999

41 Current right side tempposition (in counts)

0 to9999

42 Right side temp target position(in ratio)

0 to 255


43 Right side temp target incounts

0 to9999

44 Not used 0 to 0

RIGHT SIDE TEMPERATURE POINTER


0 to9999

46 Not used 0 to 0

47 Not used 0 to 0

48 Not used 0 to 0

49 Right side temp motor state 0 to 5


AIR INLET POINTER

PointerNumber


50 Air inlet range (in counts) 0 to9999

51 Current air inlet position (incounts)

0 to9999

52 Air inlet target position (inratio)

0 to 255


53 Air inlet target in counts 0 to9999

54 Not used 0 to 0

55 number of motor moves sincelast index

0 to9999

56 Not used 0 to 0

57 Not used 0 to 0

58 Not used 0 to 0

59 Air inlet motor state 0 to 5


60 Reserved

61 Actual Outside Air Temp (indegrees F)

-40 to215

62 Not used 0 to 0

WJ CONTROLS 24 - 23


AIR INLET POINTER

63 Engine Intake Air Temperature(in degrees F)

-40 to215

64 Vehicle speed in MPH 0 to 255

65 Engine RPM/100 -0 to 82

66 Engine Coolant Temp - 40 (indegrees F)

-40 to215

67 Country Code 0 to 255

68 Not used 0 to 0

69 Not used 0 to 0

IR SENSOR POINTER

PointerNumber


70 Thermistor temp (in degrees) -40 to215

71 Left side sensor A/D (filtered) 0 to 255

72 Right side sensor A/D (filtered) 0 to 255

73 Left side temp (in degrees F) -40 to140

74 Right side temp (in degrees F) -40 to140

75 Not used 0 to 0

76 Not used 0 to 0

77 Not used 0 to 0

78 Not used 0 to 0

79 Not used 0 to 0

IDENTIFICATION POINTER

PointerNumber


80 ROM bit pattern number (digits1,2,3 & 4)

0 to9999

81 ROM bit pattern number (digits5,6,7 & 8)

0 to9999

82 CAL bit pattern number (digits1,2,3 & 4)

0 to9999

83 CAL bit pattern number (digits5,6,7 & 8)

0 to9999

84 Not used 0 to 0

85 Not used 0 to 0

86 Not used 0 to 0

87 Not used 0 to 0

88 Not used 0 to 0

89 Not used 0 to 0

OUTPUT CIRCUIT/ACTUATOR TESTSIn the Output Circuit/Actuator Test mode, the out-

put circuits can be viewed, monitored, overridden,and tested. If a failure occurs in an output circuit,test the circuit by overriding the system. Test theactuator through its full range of operation.

(1) To begin the Output Circuit/Actuator Tests youmust be in the Select Test mode.

(2) With a “00” value displayed in the Test Selectorand no stick man, turn the rotary temperature con-trol knob until the test number you are looking forappears in the Test Selector display. See the CircuitTesting charts for a listing of the test numbers, testitems, test types, system tested, and displayed val-ues.

(3) To see the output value, depress the a/c orrecirc button. The values displayed will represent theoutput from the AZC control module.

(4) To enter the actuator test, depress the a/c orrecirc button. Then, rotate the right temperature setknob to the desired position.

REMOVAL



(2) Remove the center upper, and center lowerbezels from the instrument panel. Refer to Instru-ment Panel System for the procedures.

(3) Remove the 4 screws that secure the a/c heatercontrol to the instrument panel (Fig. 13).

(4) Pull the a/c heater control assembly away fromthe instrument panel far enough to access the con-nections on the back of the control.

(5) Unplug the wire and/or vacuum harness con-nectors from the back of the a/c heater control (Fig.14).

(6) Remove the a/c heater control from the instru-ment panel.

24 - 24 CONTROLS WJ


INSTALLATION(1) Plug the wire harness and/or vacuum harness

connectors into the back of the a/c heater control.(2) Position the a/c heater control in the instru-

ment panel and secure it with 4 screws. Tighten thescrews to 2.2 N·m (20 in. lbs.).

(3) Reinstall the center upper, and center lowerbezels onto the instrument panel. Refer to Instru-ment Panel System for the procedures.

(4) Connect the battery negative cable.

A/C HIGH PRESSURE SWITCH

DESCRIPTIONThe a/c high pressure switch is located in the dis-

charge line near the condenser. The switch isscrewed onto a fitting that contains a Schrader-typevalve, which allows the switch to be serviced withoutdischarging the refrigerant system. The dischargeline fitting is equipped with an O-ring to seal theswitch connection.

OPERATIONThe high pressure switch is connected in series

electrically with the low pressure switch betweenground and the Powertrain Control Module (PCM).The switch contacts open and close causing the PCMto turn the compressor clutch on and off. This pre-vents compressor operation when the discharge linepressure approaches high levels.

The high pressure switch contacts are open whenthe discharge line pressure rises above 3100 to 3375kPa (450 to 490 psi). The switch contacts will closewhen the discharge line pressure drops to 1860 to2275 kPa (270 to 330 psi).

The high pressure switch is a factory-calibratedunit. The switch cannot be adjusted or repaired and,if faulty or damaged, it must be replaced.

DIAGNOSIS AND TESTING - A/C HIGHPRESSURE SWITCH

Before performing diagnosis of the high pressureswitch, verify that the refrigerant system has the cor-rect refrigerant charge.



(2) Unplug the wire harness connector from thehigh pressure switch on the refrigerant system fit-ting.

(3) Check for continuity between the two terminalsof the high pressure switch. There should be continu-ity. If OK, test and repair the a/c switch sense circuitas required. If not OK, replace the faulty switch.


cable.(2) Unplug the wire harness connector from the

high pressure switch, which is mounted to a fittingon the discharge line near the condenser inlet.

(3) Unscrew the high pressure switch from the dis-charge line fitting.

(4) Remove the high pressure switch from thevehicle.

(5) Remove the O-ring seal from the discharge linefitting and discard.

INSTALLATION(1) Lubricate a new O-ring seal with clean refrig-

erant oil and install it on the discharge line fitting.Use only the specified O-rings as they are made of aspecial material for the R-134a system. Use onlyrefrigerant oil of the type recommended for the com-pressor in the vehicle.

Fig. 13 A/C HEATER CONTROL REMOVE/INSTALL1 - MOUNTING SCREW TABS

Fig. 14 A/C HEATER CONTROL CONNECTIONS1 - MODE SWITCH2 - ELECTRICAL CONNECTIONS3 - VACUUM HARNESS

WJ CONTROLS 24 - 25


(2) Install and tighten the high pressure switch onthe discharge line fitting. The switch should be hand-tightened onto the line fitting.

(3) Plug the wire harness connector into the highpressure switch.


A/C LOW PRESSURE SWITCH

DESCRIPTIONThe low pressure switch is located on the top of the

accumulator. The switch is screwed onto an accumu-lator fitting that contains a Schrader-type valve,which allows the switch to be serviced without dis-charging the refrigerant system. The accumulator fit-ting is equipped with an O-ring to seal the switchconnection.

OPERATIONThe low pressure switch is connected in series elec-

trically with the high pressure switch, betweenground and the Powertrain Control Module (PCM).The switch contacts open and close causing the PCMto turn the compressor clutch on and off. This regu-lates the refrigerant system pressure and controlsevaporator temperature. Controlling the evaporatortemperature prevents condensate water on the evap-orator fins from freezing and obstructing air condi-tioning system air flow.

The low pressure switch contacts are open whenthe suction pressure is approximately 152 kPa (22psi) or lower. The switch contacts will close when thesuction pressure rises to approximately 234 to 262kPa (34 to 38 psi) or above. Lower ambient tempera-tures, below approximately -1° C (30° F), will alsocause the switch contacts to open. This is due to thepressure/temperature relationship of the refrigerantin the system.

The low pressure switch is a factory-calibratedunit. It cannot be adjusted or repaired and, if faultyor damaged, it must be replaced.

DIAGNOSIS AND TESTING - A/C LOWPRESSURE SWITCH

Before performing diagnosis of the low pressureswitch, be certain that the switch is properlyinstalled on the accumulator fitting. If the switch istoo loose it may not open the Schrader-type valve inthe accumulator fitting, which will prevent theswitch from correctly monitoring the refrigerant sys-tem pressure.

Also verify that the refrigerant system has the cor-rect refrigerant charge. (Refer to 24 - HEATING &AIR CONDITIONING/PLUMBING - STANDARDPROCEDURE - REFRIGERANT SYSTEM CHARGE)



(2) Unplug the low pressure switch wire harnessconnector from the switch on the accumulator fitting.

(3) Install a jumper wire between the two cavitiesof the low pressure switch wire harness connector.

(4) Connect a manifold gauge set to the refrigerantsystem service ports. (Refer to 24 - HEATING & AIRCONDITIONING/PLUMBING - STANDARD PRO-CEDURE - REFRIGERANT SYSTEM SERVICEEQUIPMENT)

(5) Connect the battery negative cable.(6) Set the a/c button on, and place the a/c heater

mode control switch knob in any a/c position andstart the engine.

(7) Check for continuity between the two terminalsof the low pressure switch. There should be continu-ity with a suction pressure reading of 262 kPa (38psi) or above, and no continuity with a suction pres-sure reading of 141 kPa (20.5 psi) or below. If OK,test and repair the A/C switch sense circuit asrequired. If not OK, replace the faulty switch.


cable.(2) Unplug the wire harness connector from the

low pressure cycling clutch switch on the top of theaccumulator.

(3) Unscrew the a/c low pressure switch from thefitting on the top of the accumulator (Fig. 15).

(4) Remove the O-ring seal from the accumulatorfitting and discard.

INSTALLATION(1) Lubricate a new O-ring seal with clean refrig-

erant oil and install it on the accumulator fitting.Use only the specified O-rings as they are made of aspecial material for the R-134a system. Use onlyrefrigerant oil of the type recommended for the com-pressor in the vehicle.

(2) Install and tighten the a/c low pressure switchon the accumulator fitting. The switch should behand-tightened onto the accumulator fitting.

(3) Plug the wire harness connector into the lowpressure cycling clutch switch.


24 - 26 CONTROLS WJ

A/C HIGH PRESSURE SWITCH (Continued)

BLOWER MOTORCONTROLLER

DESCRIPTIONModels equipped with the optional Automatic Zone

Control (AZC) system have a blower motor controller.The controller allows the selection of almost infi-nitely variable blower motor speeds. The controller ismounted to the HVAC housing, under the instrumentpanel and just inboard of the blower motor, in thesame location used for the blower motor resistor onmanual temperature control systems. It can beaccessed without removing any other components.

OPERATIONThe blower motor controller output to the blower

motor can be adjusted by the blower motor speedswitch knob on the AZC A/C Heater control panel, orit can be adjusted automatically by the logic circuitryand programming of the AZC control module. Ineither case, the AZC control module sends the correctpulse width modulated signal to the blower motorcontroller to obtain the selected or programmedblower motor speed.

The blower motor controller cannot be repairedand, if faulty or damaged, it must be replaced.


cable.(2) Depress locking tab and unplug the wire har-

ness connector from the blower motor controller.(3) Depress locking tab and unplug the controller

connector from the blower motor.(4) Remove the 2 screws that secure the blower

motor controller to the HVAC housing.(5) Remove the blower motor controller from the

HVAC housing (Fig. 16).

INSTALLATION(1) Install the blower motor controller in the

HVAC housing. The housing is indexed to allow con-troller mounting in only one position. Tighten themounting screws to 2.2 N·m (20 in. lbs.).

(2) Plug in the wire harness connector to theblower motor controller.

(3) Plug in the connector from the blower motorcontroller to the blower motor.


Fig. 15 ACCUMULATOR AND SUPPORT BRACKET1 - SERVICE PORT2 - LOW PRESSURE SWITCH3 - ACCUMULATOR4 - SUPPORT BRACKET

Fig. 16 BLOWER MOTOR CONTROLLER REMOVE/INSTALL

1 - BLOWER MOTOR CONTROLLER2 - BLOWER MOTOR3 - GROUND STRAP4 - ELECTRICAL CONNECTORS5 - HEATER CORE TUBES

WJ CONTROLS 24 - 27

BLOWER MOTOR CONTROLLER (Continued)

BLOWER MOTOR RESISTORBLOCK

DESCRIPTIONModels with the standard manual temperature

control system have a blower motor resistor. Theblower motor resistor is mounted to the bottom of theHVAC housing, under the instrument panel and justinboard of the blower motor. It can be accessed forservice without removing any other components.

OPERATIONThe resistor has multiple resistor wires, each of

which will reduce the current flow to the blowermotor to change the blower motor speed by changingthe resistance in the blower motor ground path. Theblower motor switch directs the ground path throughthe correct resistor wire to obtain the selected speed.

With the blower motor switch in the lowest speedposition, the ground path for the motor is appliedthrough all of the resistor wires. Each higher speedselected with the blower motor switch applies theblower motor ground path through fewer of the resis-tor wires, increasing the blower motor speed. Whenthe blower motor switch is in the highest speed posi-tion, the blower motor resistor is bypassed and theblower motor receives a direct path to ground.

The blower motor resistor cannot be repaired and,if faulty or damaged, it must be replaced.

DIAGNOSIS AND TESTING - BLOWER MOTORRESISTOR BLOCK




(2) Unplug the wire harness connector from theblower motor resistor.

(3) Check for continuity between each of theblower motor switch input terminals of the resistorand the resistor output terminal. In each case thereshould be continuity. If OK, repair the wire harnesscircuits between the blower motor switch and theblower motor resistor or blower motor as required. Ifnot OK, replace the faulty blower motor resistor.


cable.(2) Depress locking tab and unplug the wire har-

ness connector from the blower motor resistor.(3) Depress locking tab and unplug the resistor

connector from the blower motor.(4) Remove the 2 screws that secure the blower

motor resistor to the HVAC housing.(5) Remove the blower motor resistor from the

HVAC housing (Fig. 17).

INSTALLATION(1) Install the blower motor resistor in the HVAC

housing. The housing is indexed to allow mounting inonly one position. Tighten the mounting screws to 2.2N·m (20 in. lbs.).

(2) Plug in the wire harness connector to theblower motor resistor.

(3) Plug in the connector from the blower motorresistor to the blower motor.

Fig. 17 BLOWER MOTOR RESISTOR REMOVE/INSTALL

1 - BLOWER MOTOR RESISTOR/CONTROLLER2 - BLOWER MOTOR3 - GROUND STRAP4 - ELECTRICAL CONNECTORS5 - HEATER CORE TUBES

24 - 28 CONTROLS WJ


BLOWER MOTOR SWITCH

DESCRIPTIONThe A/C Heater blower motor is controlled by a

rotary-type blower motor switch, mounted in the A/CHeater control panel. On vehicles with manual tem-perature control systems, the switch allows the selec-tion of four blower motor speeds, but will onlyoperate with the ignition switch in the On positionand the A/C Heater mode control switch in any posi-tion, except Off. On vehicles with the Automatic ZoneControl (AZC) systems, the switch allows the selec-tion of Lo Auto, Hi Auto, and ten speed settingsbetween Lo and Hi.

OPERATIONOn manual temperature control systems, the

blower motor switch is connected in series with theblower motor ground path through the a/c heatermode control switch. The blower motor switch directsthis ground path to the blower motor through theblower motor resistor wires, or directly to the blowermotor, as required to achieve the selected blowermotor speed.

On AZC systems, the blower motor switch is justone of many inputs to the AZC control module. In themanual blower modes, the AZC control moduleadjusts the blower motor speed through the blowermotor controller as required to achieve the selectedblower switch position. In the auto blower modes, theAZC control assembly is programmed to select andadjust the blower motor speed through the blowermotor controller as required to achieve and maintainthe selected comfort level.

The blower motor switch cannot be repaired and, iffaulty or damaged, it must be replaced. The switch isserviced only as a part of the a/c heater controlassembly.

DIAGNOSIS AND TESTING - BLOWER MOTORSWITCH-MANUAL TEMPERATURE CONTROLSYSTEM


WARNING: ON VEHICLES EQUIPPED WITH AIR-BAGS, DISABLE THE AIRBAG SYSTEM BEFOREATTEMPTING ANY STEERING WHEEL, STEERINGCOLUMN, OR INSTRUMENT PANEL COMPONENTDIAGNOSIS OR SERVICE. DISCONNECT AND ISO-LATE THE BATTERY NEGATIVE (GROUND) CABLE,THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-TEM CAPACITOR TO DISCHARGE BEFORE PER-

FORMING FURTHER DIAGNOSIS OR SERVICE. THISIS THE ONLY SURE WAY TO DISABLE THE AIRBAGSYSTEM. FAILURE TO TAKE THE PROPER PRE-CAUTIONS COULD RESULT IN AN ACCIDENTALAIRBAG DEPLOYMENT AND POSSIBLE PERSONALINJURY.

(1) Check for battery voltage at the fuse in thePower Distribution Center (PDC). If OK, go to Step2. If not OK, repair the shorted circuit or componentas required and replace the faulty fuse.

(2) Turn the ignition switch to the Off position.Disconnect and isolate the battery negative cable.Remove the a/c heater control from the instrumentpanel. (Refer to 24 - HEATING & AIR CONDITION-ING/CONTROLS/A/C HEATER CONTROL -REMOVAL) Check for continuity between the groundcircuit cavity of the a/c heater control wire harnessconnector and a good ground. There should be conti-nuity. If OK, go to Step 3. If not OK, repair the opencircuit to ground as required.

(3) With the a/c heater control wire harness con-nector unplugged, place the a/c heater mode controlswitch knob in any position except the Off position.Check for continuity between the ground circuit ter-minal and each of the blower motor driver circuit ter-minals of the a/c heater control as you move theblower motor switch knob to each of the four speedpositions. There should be continuity at each drivercircuit terminal in only one blower motor switchspeed position. If OK, test and repair the blowerdriver circuits between the a/c heater control connec-tor and the blower motor resistor as required. If notOK, replace the faulty a/c heater control unit.

REMOVAL


The blower motor switch cannot be adjusted orrepaired, and if faulty or damaged, the a/c heatercontrol must be replaced. (Refer to 24 - HEATING &AIR CONDITIONING/CONTROLS/A/C HEATERCONTROL - REMOVAL)

WJ CONTROLS 24 - 29

BLOWER MOTOR RESISTOR BLOCK (Continued)

IN-CAR TEMPERATURESENSOR

DESCRIPTIONModels equipped with the optional Automatic Zone

Control (AZC) system use automatic dual zone tem-perature control with infrared sensing technology.The temperature sensor is located in the centerinstrument panel, between the dual temperatureknobs of the AZC.

OPERATIONThe Automatic Zone Control uses infrared sensing

technology to control occupant comfort levels, not theactual passenger compartment air temperature. Dualinfrared sensors mounted in the face of the controlunit independently measure the surface temperatureto maintain customer-perceived comfort temperatureunder changing conditions. Dual Zone temperaturecontrol provides wide side-to-side variation in comforttemperature to exceed the needs of either front seatoccupant. This sensing system replaces interior airtemperature and solar sensors used to approximatedirect sensing control through complex control pro-grams.

The infrared temperature sensor cannot beadjusted or repaired and, if faulty or damaged, theAZC head must be replaced.

NOTE: The infrared sensor window may be perma-nently damaged if any type of cosmetic vinyl dress-ings are allowed to contact the lens. Avoid sprayingor wiping this area with any cleaner or conditioner.This may result in impaired temperature sensingand control.

REMOVALThe infrared temperature sensor cannot be

adjusted or repaired and, if faulty or damaged, theAZC head must be replaced. (Refer to 24 - HEATING& AIR CONDITIONING/CONTROLS/A/C HEATERCONTROL - REMOVAL)

BLEND DOOR ACTUATOR

DESCRIPTIONThe blend door for all models is actuated by an

electric actuator, while the AZC system uses 2 sepa-rate actuators to allow the driver and passenger toselect individual comfort levels. In the following pro-cedures, service for both types of actuators is cov-ered.

REMOVAL


The blend door actuator is used on all models,whether equipped with manual or Automatic ZoneControl (AZC). This actuator is located on the front ofthe HVAC housing to the right of the floor paneltransmission tunnel, and can be removed from thepassenger compartment without instrument panel orHVAC housing removal.


(2) Remove the glove box door. Refer to InstrumentPanel System for the procedures.

(3) Remove the lower I/P glove box door surroundpanel. Refer to Instrument Panel System for the pro-cedures.

(4) Unplug the wire harness connector from theblend door actuator (Fig. 18).

Fig. 18 BLEND DOOR ACTUATOR1 - BLEND DOOR ACTUATOR2 - ELECTRICAL CONNECTOR

24 - 30 CONTROLS WJ

(5) Remove the 2 screws that secure the blenddoor actuator to the HVAC housing.

(6) Remove the blend door actuator from theHVAC housing.

INSTALLATION(1) Install the blend door actuator on the HVAC

housing and tighten the two mounting screws to 2.2N·m (20 in. lbs.).

(2) Plug in the wire harness connector to the blenddoor actuator.

(3) Install the glove box door. Refer to InstrumentPanel System for the procedures.

(4) Install the lower I/P glove box door surroundpanel. Refer to Instrument Panel System for the pro-cedures.

(5) Connect and the battery negative cable.

MODE DOOR ACTUATOR

DESCRIPTIONThe mode door actuators for vehicles equipped with

the standard equipment manual temperature controlsystem are vacuum controlled. The optional Auto-matic Zone Control (AZC) system uses electric motorsto actuate all mode doors. The service procedures forboth types of actuators are covered by the followingprocedures.

REMOVAL - HEAT/DEFROST - PANEL/DEFROSTDOOR ELECTRIC ACTUATOR


These actuators are used only on models equippedwith the optional Automatic Zone Control (AZC) sys-tem.


(2) Remove the two bolts that secure the centerinstrument panel support bracket to the left side ofthe floor panel transmission tunnel.

(3) Remove the two bolts that secure the centerinstrument panel support bracket to the instrumentpanel.

(4) Remove the center instrument panel supportbracket from the vehicle.

(5) Unplug the wire harness connector from theheat/defrost - panel/defrost door actuator (Fig. 19).

(6) Remove the three screws that secure the heat/defrost-panel/defrost door motor to the HVAC hous-ing.

(7) Remove the heat/defrost-panel/defrost doormotor from the HVAC housing.

Fig. 19 HEAT/DEFROST - PANEL/DEFROST DOORACTUATOR

1 - LEVER ASSEMBLY2 - LINKAGE3 - ELECTRIC ACTUATOR

WJ CONTROLS 24 - 31

BLEND DOOR ACTUATOR (Continued)

REMOVAL - HEAT/DEFROST DOOR VACUUMACTUATOR


This actuator is used only on models equipped withthe standard manual temperature control system.

(1) Remove the HVAC housing from the vehicle.(Refer to 24 - HEATING & AIR CONDITIONING/DISTRIBUTION/HVAC HOUSING - REMOVAL)

(2) Unplug the vacuum harness connector from theheat/defrost door vacuum actuator (Fig. 20).

(3) Disengage the heat/defrost door pivot connec-tion from the heat/defrost door pivot pin.

(4) Remove the screws that secure the heat/defrostdoor vacuum actuator to the HVAC housing.

(5) Remove the heat/defrost door vacuum actuatorfrom the HVAC housing.

REMOVAL - PANEL/DEFROST DOOR VACUUMACTUATOR




(2) Unplug the vacuum harness connector from theheat/defrost door vacuum actuator (Fig. 21).

(3) Disengage the panel/defrost door pivot connec-tion from the panel/defrost door pivot pin.

(4) Remove the screws that secure the panel/de-frost door vacuum actuator to the HVAC housing.

(5) Remove the panel/defrost door vacuum actuatorfrom the HVAC housing.

INSTALLATION - HEAT/DEFROST - PANEL/DEFROST DOOR ELECTRIC ACTUATOR

(1) Install the heat/defrost-panel/defrost dooractuator on the HVAC housing, and tighten the threemounting screws to 2.2 N·m (20 in. lbs.).

(2) Plug in the wire harness connector to the heat/defrost - panel/defrost door actuator.

(3) Install the center instrument panel supportbracket on the vehicle.

(4) Install the two bolts that secure the centerinstrument panel support bracket to the instrumentpanel.

(5) Install the two bolts that secure the centerinstrument panel support bracket to the left side ofthe floor panel transmission tunnel.


Fig. 20 MODE DOOR ACTUATORS-MANUALSYSTEM

1 - VACUUM LINES2 - ACTUATING LEVERS3 - LINKAGE4 - VACUUM ACTUATORS5 - ACTUATING LEVER

24 - 32 CONTROLS WJ

MODE DOOR ACTUATOR (Continued)

INSTALLATION - HEAT/DEFROST DOORVACUUM ACTUATOR

(1) Install the heat/defrost door vacuum actuatoron the HVAC housing and tighten the mountingscrews to 2.2 N·m (20 in. lbs.).

(2) Engage the heat/defrost door pivot connectionwith the heat/defrost door pivot pin.

(3) Plug in the vacuum harness connector to theheat/defrost door vacuum actuator.

(4) Install the HVAC housing in the vehicle. (Referto 24 - HEATING & AIR CONDITIONING/DISTRI-BUTION/HVAC HOUSING - INSTALLATION)

INSTALLATION - PANEL/DEFROST DOORVACUUM ACTUATOR

(1) Install the panel/defrost door vacuum actuatoron the HVAC housing and tighten the mountingscrews to 2.2 N·m (20 in. lbs.).

(2) Engage the panel/defrost door pivot connectionwith the panel/defrost door pivot pin.

(3) Plug in the vacuum harness connector to theheat/defrost door vacuum actuator.


RECIRCULATION DOORACTUATOR

DESCRIPTIONThe recirculation door actuator for vehicles

equipped with the standard equipment manual tem-perature control system is vacuum controlled. Theoptional Automatic Zone Control (AZC) system usesan electric recirculation door actuator. In the follow-ing procedures, service for both types of actuators iscovered.

REMOVAL - RECIRCULATION DOOR VACUUMACTUATOR



(1) Remove the instrument panel from the vehicle.Refer to Instrument Panel System for the procedures.

(2) Unplug the vacuum harness connector from therecirculation door vacuum actuator.

(3) Disengage the recirculation door pivot connec-tion from the door pivot pin.

(4) Disengage the recirculation door actuating rodfrom the recirculation door lever.

(5) Remove the screws that secure the recircula-tion door vacuum actuator to the HVAC housing.

(6) Remove the recirculation door vacuum actuatorfrom the HVAC housing.

Fig. 21 PANEL/DEFROST DOOR ACTUATOR1 - VACUUM LINE2 - PANEL/DEFROST DOOR ACTUATOR3 - SHAFT RETAINER

WJ CONTROLS 24 - 33

MODE DOOR ACTUATOR (Continued)

REMOVAL - RECIRCULATION DOOR ELECTRICACTUATOR


This actuator is used only on models equipped withthe optional Automatic Zone Control (AZC) system.


(2) Unplug the wire harness connector from therecirculation door actuator.

(3) Remove the 2 screws securing the recirculationdoor housing to the HVAC unit (Fig. 22). Tilt thefront of the housing up while reaching around theback releasing 2 tangs holding the rear of the hous-ing down.

(4) Remove the recirculation door housing from theHVAC unit.

(5) Remove the screws that secure the recircula-tion door actuator to the HVAC housing.

(6) Remove the recirculation door actuator fromthe HVAC housing.

INSTALLATION - RECIRCULATION DOORVACUUM ACTUATOR

(1) Install the recirculation door vacuum actuatoron the HVAC housing and tighten the mountingscrews to 2.2 N·m (20 in. lbs.).

(2) Engage the recirculation door actuating rodwith the recirculation door lever.

(3) Engage the recirculation door pivot connectionwith the door pivot pin.

(4) Plug in the vacuum harness connector to therecirculation door vacuum actuator.

(5) Install the instrument panel in the vehicle.Refer to Instrument Panel System for the procedures.

INSTALLATION - RECIRCULATION DOORELECTRIC ACTUATOR

(1) Install the recirculation door actuator on therecirculation door housing and tighten the mountingscrews to 2.2 N·m (20 in. lbs.).

(2) Install the recirculation door housing on theHVAC unit and tighten the mounting screws to 2.2N·m (20 in. lbs.).

(3) Plug in the wire harness connector to the recir-culation door actuator.


VACUUM CHECK VALVE

DESCRIPTIONTwo vacuum check valves (non AZC only) are

installed on the vacuum supply system. One is on theaccessory vacuum supply line in the engine compart-ment, near the vacuum tap on the engine intakemanifold. A second vacuum check valve is located onthe bottom of the HVAC unit behind the passengerfront floor duct on the black vacuum line. The vac-uum check valves are designed to allow vacuum toflow in only one direction through the accessory vac-uum supply circuits.

OPERATIONThe use of a vacuum check valve helps to maintain

the system vacuum needed to retain the selected A/CHeater mode settings. The check valve will preventthe engine from bleeding down system vacuumthrough the intake manifold during extended heavyengine load (low engine vacuum) operation.

Fig. 22 RECIRCULATION DOOR HOUSING1 - RECIRCULATION DOOR HOUSING2 - ATTACHING SCREWS

24 - 34 CONTROLS WJ

RECIRCULATION DOOR ACTUATOR (Continued)

The vacuum check valve cannot be repaired and, iffaulty or damaged, it must be replaced.

REMOVAL(1) Unplug the HVAC vacuum supply line connec-

tor at the vacuum check valve near the engine intakemanifold vacuum adapter fitting.

(2) Note the orientation of the check valve in thevacuum supply line for correct installation.

(3) Unplug the vacuum check valve from the vac-uum supply line fittings.

INSTALLATION(1) Plug in the vacuum check valve at the vacuum

supply line fittings, noting the orientation of thecheck valve in the vacuum supply line for correctinstallation.

(2) Plug in the HVAC vacuum supply line connec-tor at the vacuum check valve near the engine intakemanifold vacuum adapter fitting.

VACUUM RESERVOIR

DESCRIPTIONThe vacuum reservoir is mounted in the right front

of the vehicle behind the headlamp mounting module(Fig. 23). The headlamp mounting module and head-lamp assembly must be removed from the vehicle toaccess the vacuum reservoir for service. Refer toLamps/Lighting for the procedures.

OPERATIONEngine vacuum is stored in the vacuum reservoir.

The stored vacuum is used to operate the vacuum-controlled vehicle accessories during periods of lowengine vacuum such as when the vehicle is climbinga steep grade, or under other high engine load oper-ating conditions.

The vacuum reservoir cannot be repaired and, iffaulty or damaged, it must be replaced.

REMOVAL(1) Remove the right side headlamp mounting

module and headlamp assembly. Refer to Lamps/Lighting for the procedures.

(2) Remove the two screws that secure the vacuumreservoir to the base of the radiator closure panel.

(3) Remove the vacuum reservoir.

INSTALLATION(1) Install the vacuum reservoir in the vehicle and

tighten the two screws to 3.4 N·m (30 in. lbs.).(2) Install the right side headlamp mounting mod-

ule and headlamp assembly. Refer to Lamps/Lightingfor the procedures.

Fig. 23 VACUUM RESERVOIR1 - FAN RELAY2 - SPEED CONTROL SERVO3 - VACUUM RESERVOIR

WJ CONTROLS 24 - 35

VACUUM CHECK VALVE (Continued)

DISTRIBUTION

TABLE OF CONTENTS

page page

AIR OUTLETSREMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36INSTALLATION. . . . . . . . . . . . . . . . . . . . . . . . . . . 36

BLOWER MOTORDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . 37OPERATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37DIAGNOSIS AND TESTING . . . . . . . . . . . . . . . . . 37

BLOWER MOTOR . . . . . . . . . . . . . . . . . . . . . . 37REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38INSTALLATION. . . . . . . . . . . . . . . . . . . . . . . . . . . 38

DEFROSTER DUCTSREMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38INSTALLATION. . . . . . . . . . . . . . . . . . . . . . . . . . . 39

FLOOR DISTRIBUTION DUCTSREMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39INSTALLATION. . . . . . . . . . . . . . . . . . . . . . . . . . . 39

INSTRUMENT PANEL DUCTSREMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

INSTALLATION. . . . . . . . . . . . . . . . . . . . . . . . . . . 39REAR FLOOR HEAT DUCT

REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40INSTALLATION. . . . . . . . . . . . . . . . . . . . . . . . . . . 41

HVAC HOUSINGREMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41DISASSEMBLY. . . . . . . . . . . . . . . . . . . . . . . . . . . 41ASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44INSTALLATION. . . . . . . . . . . . . . . . . . . . . . . . . . . 45

BLEND DOORREMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46INSTALLATION. . . . . . . . . . . . . . . . . . . . . . . . . . . 46

MODE DOORREMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46INSTALLATION. . . . . . . . . . . . . . . . . . . . . . . . . . . 49

RECIRCULATION DOORREMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49INSTALLATION. . . . . . . . . . . . . . . . . . . . . . . . . . . 50

AIR OUTLETS

REMOVALThe driver side, and passenger side panel outlets

are available for service. The center outlets are onlyserviced as part of the instrument cluster centerbezel unit.

(1) Remove the instrument panel top pad from theinstrument panel. Refer to Instrument Panel Systemfor the procedures.

(2) Remove the two screws that secure each outletto the backside of the instrument panel top pad (Fig.1).

(3) Remove the outlet from the top pad.

INSTALLATION(1) Fasten the outlet to the top pad. Tighten the

mounting screws to 2.2 N·m (20 in. lbs.).(2) Install the instrument panel top pad on the

instrument panel. Refer to Instrument Panel Systemfor the procedures.

Fig. 1 PANEL OUTLETS (PASSENGER SIDE)1 - MOUNTING SCREWS2 - MOUNTING SCREWS3 - PANEL OUTLETS

24 - 36 DISTRIBUTION WJ

BLOWER MOTOR

DESCRIPTIONThe blower motor and blower wheel are located in

the passenger side end of the HVAC housing, belowthe glove box module. The blower motor controls thevelocity of the air flowing through the HVAC housingby spinning a squirrel cage-type blower wheel withinthe housing at the selected speed. The blower motorand blower wheel can be serviced from the passengercompartment side of the housing.

OPERATIONThe blower motor will only operate when the igni-

tion switch is in the On position, and the a/c heatermode control switch is in any position, except off. Theblower motor circuit is protected by a fuse in thejunction block. On models with the standard manualtemperature control system, the blower motor speedis controlled by regulating the battery feed throughthe blower motor switch and the blower motor resis-tor. On models with the optional Automatic ZoneControl (AZC) system, the blower motor speed is con-trolled by using Pulse Width Modulation (PWM). Theblower motor controller adjusts the battery feed volt-age to the blower motor, based upon an input fromthe blower motor switch, through the AZC controlmodule. Pulse width modulation of blower powerallows the blower to operate at any speed from sta-tionary, to full speed.

The blower motor and blower motor wheel cannotbe repaired, and if faulty or damaged, they must bereplaced. The blower motor and blower wheel areeach serviced separately.

DIAGNOSIS AND TESTING - BLOWER MOTOR

WARNING: ON VEHICLES EQUIPPED WITH AIR-BAGS, DISABLE THE AIRBAG SYSTEM BEFOREATTEMPTING ANY STEERING WHEEL, STEERINGCOLUMN, OR INSTRUMENT PANEL COMPONENTDIAGNOSIS OR SERVICE. DISCONNECT AND ISO-LATE THE BATTERY NEGATIVE (GROUND) CABLE,THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-TEM CAPACITOR TO DISCHARGE BEFORE PER-FORMING FURTHER DIAGNOSIS OR SERVICE. THISIS THE ONLY SURE WAY TO DISABLE THE AIRBAG

SYSTEM. FAILURE TO TAKE THE PROPER PRE-CAUTIONS COULD RESULT IN AN ACCIDENTALAIRBAG DEPLOYMENT AND POSSIBLE PERSONALINJURY.

For circuit descriptions and diagrams, refer to theappropriate wiring information. Possible causes of aninoperative blower motor include:

• Faulty fuse• Faulty blower motor circuit wiring or wire har-

ness connections• Faulty blower motor resistor (if the vehicle is so

equipped)• Faulty blower motor controller (if the vehicle is

so equipped)• Faulty blower motor switch• Faulty a/c heater mode control switch• Faulty blower motor.Possible causes of the blower motor not operating

in all speeds include:• Faulty fuse• Faulty blower motor switch• Faulty blower motor resistor (if the vehicle is so

equipped)• Faulty blower motor controller (if the vehicle is

so equipped)• Faulty AZC module (if the vehicle is so

equipped)• Faulty blower motor circuit wiring or wire har-

ness connections.

VIBRATIONPossible causes of blower motor vibration include:• Improper blower motor mounting• Improper blower wheel mounting• Blower wheel out of balance or bent• Blower motor faulty.

NOISETo verify that the blower is the source of the noise,

unplug the blower motor wire harness connector andoperate the HVAC system. If the noise goes away,possible causes include:

• Foreign material in the HVAC housing• Improper blower motor mounting• Improper blower wheel mounting• Blower motor faulty.

WJ DISTRIBUTION 24 - 37

REMOVAL



(2) Pinch the connector retainer and unplug theblower motor wire harness from the blower motor(Fig. 2).

(3) Remove the three screws that secure theblower motor and blower wheel assembly to theHVAC housing, using either a T-25 Torxt head orflat-bladed screwdriver.

(4) Lower the blower motor and wheel from theHVAC housing.

(5) Remove the blower wheel retainer clip (Fig. 3).(6) Remove the wheel from the blower motor shaft.

INSTALLATION(1) Press the blower wheel hub onto the blower

motor shaft. Be sure the flat on the blower motorshaft is indexed to the flat on the inside of the blowerwheel hub.

(2) Install the retainer clip over the blower wheelhub.

(3) Install the blower motor in the HVAC housingwith three mounting screws. Tighten the mountingscrews to 2.2 N·m (20 in. lbs.).

(4) Plug the blower motor wire harness connectorinto the blower motor socket.


DEFROSTER DUCTS

REMOVAL(1) Remove the instrument panel assembly from

the vehicle. See Instrument Panel System for theprocedures.

(2) Remove the three screws that secure thedefroster duct to the HVAC unit housing (Fig. 4).

Fig. 2 BLOWER MOTOR (HOUSING REMOVEDFROM VEHICLE)

1 - BLOWER MOTOR RESISTOR/CONTROLLER2 - BLOWER MOTOR3 - GROUND STRAP4 - ELECTRICAL CONNECTORS5 - HEATER CORE TUBES

Fig. 3 BLOWER MOTOR WHEEL REMOVE/INSTALL1 - BLOWER MOTOR WHEEL2 - RETAINER CLIP


BLOWER MOTOR (Continued)

(3) Remove the defroster duct from the HVAC unithousing.

INSTALLATION(1) Install the defroster duct on the HVAC unit

housing.(2) Install the three screws that secure the

defroster duct to the HVAC unit housing. Tighten themounting screws to 2.2 N·m (20 in. lbs.).

(3) Install the instrument panel assembly in thevehicle. See Instrument Panel System for the proce-dures.

FLOOR DISTRIBUTION DUCTS

REMOVAL(1) To remove the driver side floor duct from the

vehicle, remove the knee blocker panel for access toattaching screw. See Instrument Panel System forthe procedures.

(2) The passenger side floor duct fastener can beaccessed under the right-center instrument panel.

(3) Remove the screw that secures the floor duct(s)to the HVAC housing (Fig. 5).

INSTALLATION(1) Attach the floor duct(s) to the HVAC housing.(2) Install the screw that secures the floor duct(s)

to the HVAC housing. Tighten the mounting screwsto 2.2 N·m (20 in. lbs.).

(3) Install the knee blocker panel. See InstrumentPanel System for the procedures.

INSTRUMENT PANEL DUCTS

REMOVAL(1) Remove the instrument panel top pad from the

vehicle. See Instrument Panel System for the proce-dure.

(2) Unsnap the duct extension(s) from the instru-ment panel structural duct assembly (Fig. 6).

(3) Remove the duct extension(s) from the instru-ment panel (Fig. 7).

INSTALLATION(1) Connect the duct extension(s) to the instru-

ment panel.(2) Snap the duct extension(s) to the instrument

panel structural duct assembly.

Fig. 4 HVAC DEFROSTER DUCT1 - HVAC UNIT HOUSING2 - INSTRUMENT PANEL3 - SCREWS4 - DEFROSTER DUCT

Fig. 5 FLOOR DUCTS (HOUSING REMOVED)1 - FLOOR DUCT ADAPTER2 - HEAT/DEFROST DOOR SUB-ASSEMBLY3 - DOOR LEVERS4 - LOWER HOUSING5 - FLOOR DUCTS6 - LINKAGE7 - RETAINING TABS


DEFROSTER DUCTS (Continued)

(3) Install the instrument panel top pad in thevehicle. See Instrument Panel System for the proce-dure.

REAR FLOOR HEAT DUCT

REMOVAL(1) To remove the rear floor ducts from the vehicle,

remove the knee blocker panels for access, and pullcarpeting back.

(2) Pull the floor ducts from the HVAC housing(Fig. 8).

NOTE: The ductwork running from the HVAC hous-ing rearward through the passenger compartment ismolded into the carpeting, and must be replaced asa unit if damaged.

Fig. 6 INSTRUMENT PANEL STRUCTURAL DUCT ASSEMBLY1 - CENTER DUCT 2 - INSTRUMENT PANEL STRUCTURAL DUCT ASSEMBLY

3 - PANEL DUCT EXTENSIONS

Fig. 7 INSTRUMENT PANEL DUCT EXTENSION1 - INSTRUMENT PANEL STRUCTURAL DUCT ASSEMBLY2 - PANEL DUCT EXTENSION

Fig. 8 REAR FLOOR DUCTS1 - LEFT REAR PASSENGER FLOOR AIR DUCT2 - RIGHT REAR PASSENGER FLOOR AIR DUCT3 - TO CARPET DUCT4 - TO CARPET DUCT


INSTRUMENT PANEL DUCTS (Continued)

INSTALLATION(1) Attach the floor ducts to the HVAC housing.(2) Install the knee blocker panels, and install the

carpeting back in its original position.

HVAC HOUSING

REMOVALThe HVAC housing assembly must be removed

from the vehicle and the two halves of the housingseparated for service access of the heater core, evap-orator coil, blend door(s), and each of the variousmode doors.


WARNING: REVIEW THE WARNINGS AND CAU-TIONS IN PLUMBING BEFORE PERFORMING THEFOLLOWING OPERATION. (Refer to 24 - HEATING &AIR CONDITIONING/PLUMBING - WARNING) (Referto 24 - HEATING & AIR CONDITIONING/PLUMBING -CAUTION)



(3) Recover the refrigerant from the refrigerantsystem. (Refer to 24 - HEATING & AIR CONDI-TIONING/PLUMBING - STANDARD PROCEDURE -REFRIGERANT RECOVERY)

(4) Disconnect the liquid line refrigerant line fromthe evaporator inlet tube. Install plugs in, or tapeover all of the opened refrigerant line fittings.

(5) Disconnect the suction line refrigerant linefrom the evaporator outlet tube. Install plugs in, ortape over all of the opened refrigerant line fittings.

(6) Disconnect the heater hoses from the heatercore tubes. Clamp off the heater hoses to prevent lossof coolant. Refer to Cooling for the procedures. Installplugs in, or tape over the opened heater core tubes.

(7) If the vehicle is equipped with the manual tem-perature control system, unplug the HVAC systemvacuum supply line connector from the tee fittingnear the heater core tubes.

(8) Remove the coolant reserve/overflow bottlefrom the passenger side inner fender shield. Refer toCooling for the procedures.

(9) Remove the Powertrain Control Module (PCM)from the passenger side dash panel in the enginecompartment and set it aside. Do not unplug thePCM wire harness connectors. Refer to ElectronicControl Modules for the procedures.

(10) Remove the nuts from the HVAC housingmounting studs on the engine compartment side ofthe dash panel (Fig. 9).

(11) Remove the rear floor heat ducts from thefloor heat duct outlets (Fig. 10).

(12) Unplug the HVAC housing wire harness con-nectors.

(13) Remove the HVAC housing mounting nutsfrom the studs on the passenger compartment side ofthe dash panel (Fig. 11).

(14) Remove the HVAC housing from the vehicle,ensuring that the interior is covered in case of loss offluids.

DISASSEMBLY(1) Remove the HVAC housing from the vehicle.

(Refer to 24 - HEATING & AIR CONDITIONING/DISTRIBUTION/HVAC HOUSING - REMOVAL)

(2) Place the HVAC housing with the tubing sidedown on a work bench, making allowance for leakageof fluids.

Fig. 9 HVAC HOUSING REMOVE/INSTALL1 - EVAPORATOR LINES2 - HEATER CORE LINES3 - HVAC UNIT4 - BODY ASSEMBLY


REAR FLOOR HEAT DUCT (Continued)

(3) Using a sharp knife, split the foam seal sur-rounding the panel outlet opening, at the dividingline of the upper and lower cases (Fig. 12).

(4) Place the HVAC housing in the upright positionon the work bench.

(5) Remove the mode door actuator on the left sideof the housing, which controls the mode door in thetop of the case (Fig. 13) (Fig. 14).

Fig. 10 REAR FLOOR DUCTS1 - LEFT REAR PASSENGER FLOOR AIR DUCT2 - RIGHT REAR PASSENGER FLOOR AIR DUCT3 - TO CARPET DUCT4 - TO CARPET DUCT

Fig. 11 HVAC HOUSING REMOVE/INSTALL1 - BODY ASSEMBLY2 - HVAC UNIT

Fig. 12 SPLIT FOAM SEAL AT PANEL OUTLET1 - ONE PIECE FOAM SEAL2 - FLOOR DUCT3 - TO REAR PASSENGER FLOOR AIR DUCT

Fig. 13 MODE DOOR ACTUATORS - MANUALSYSTEM

1 - VACUUM LINES2 - ACTUATING LEVERS3 - LINKAGE4 - VACUUM ACTUATORS5 - ACTUATING LEVER


HVAC HOUSING (Continued)

(6) Remove the screw with plastic washer holdingthe lever assembly to the upper case section, andmove aside (Fig. 15).

(7) Remove the 5 clips that secure the two housinghalves to each other. There are 2 on either side atthe center, and 1 located at the forward end of themode door side of the case (Fig. 16).

(8) Release the wire harness electrical connector(s)from the mounts on the lower case at the blowermotor end of the unit (Fig. 17).

Fig. 14 MODE DOOR ACTUATOR - AZC SYSTEM1 - LEVER ASSEMBLY2 - LINKAGE3 - ELECTRIC ACTUATOR

Fig. 15 REMOVE SCREW WITH PLASTIC WASHER1 - SCREW WITH PLASTIC WASHER2 - ELECTRIC ACTUATOR

Fig. 16 HVAC HOUSING CLIPS1 - ACTUATING LEVERS AND LINKAGE2 - HOUSING CLIP

Fig. 17 WIRE HARNESS ELECTRICALCONNECTOR(S)

1 - BLOWER MOTOR RESISTOR2 - BLOWER MOTOR3 - GROUND STRAP4 - ELECTRICAL CONNECTORS5 - HEATER CORE TUBES



(9) Remove the 10 screws that secure the twohousing halves to each other.

(10) Separate the top half of the HVAC housingfrom the bottom half (Fig. 18).

NOTE: The blend door sub-assembly is attached tothe housing with 2 screws, and may be removed forservice (Fig. 19).

ASSEMBLY(1) Place the top half of the HVAC housing on the

bottom half. Be certain that each of the door pivotpins align with the pivot holes in the HVAC housing.

(2) Install the 10 screws that secure the two hous-ing halves to each other. Tighten the HVAC housingscrews to 2.2 N·m (20 in. lbs.).

(3) Attach the wire harness electrical connector(s)to the mounts on the lower case at the blower motorend of the unit.

(4) Install the 5 clips that secure the two housinghalves to each other. Check doors for binding afterreplacement, and after assembly of housing.

(5) Install the screw with plastic washer holdingthe lever assembly to the upper case section.

(6) Install the mode door actuator on the left sideof the housing.

Fig. 18 UPPER AND LOWER HVAC HOUSING - SEPARATED1 - ELECTRICAL CONNECTORS2 - VACUUM ACTUATOR3 - RECIRCULATION DOOR4 - BLOWER MOTOR RESISTOR/CONTROLLER5 - BLOWER WHEEL6 - EVAPORATOR AND TUBES7 - BLEND DOOR8 - PIVOT SHAFT(MOTOR REMOVED)

9 - PANEL/OUTLET DOOR10 - LOWER HOUSING11 - VACUUM ACTUATORS12 - UPPER HOUSING13 - VACUUM HARNESS14 - HEATER CORE AND TUBES



INSTALLATION

WARNING: REVIEW THE WARNINGS AND CAU-TIONS IN PLUMBING BEFORE PERFORMING THEFOLLOWING OPERATION. (Refer to 24 - HEATING &AIR CONDITIONING/PLUMBING - WARNING) (Referto 24 - HEATING & AIR CONDITIONING/PLUMBING -CAUTION)

Any kinks or sharp bends in the refrigerant plumb-ing will reduce the capacity of the entire air condi-tioning system. Kinks and sharp bends reduce theflow of refrigerant in the system. A good rule for theflexible hose refrigerant lines is to keep the radius ofall bends at least ten times the diameter of the hose.In addition, the flexible hose refrigerant lines shouldbe routed so they are at least 80 millimeters (3inches) from the exhaust manifold.

High pressures are produced in the refrigerant sys-tem when the air conditioning compressor is operat-ing. Extreme care must be exercised to make surethat each of the refrigerant system connections ispressure-tight and leak free. It is a good practice toinspect all flexible hose refrigerant lines at least oncea year to make sure they are in good condition andproperly routed.

(1) Position the HVAC housing to the dash panel.Be certain that the evaporator condensate drain tubeand the housing mounting studs are inserted intotheir correct mounting holes.

(2) Install the HVAC housing mounting nuts to thestuds on the passenger compartment side of the dashpanel. Tighten the nuts to 4.5 N·m (40 in. lbs.).

(3) Connect the HVAC housing wire harness con-nectors.

(4) Reinstall the rear floor heat ducts to the centerfloor heat duct outlets.

(5) Install and tighten the nuts onto the HVAChousing mounting studs on the engine compartmentside of the dash panel. Tighten the nuts to 7 N·m (60in. lbs.).

(6) Reinstall the PCM to the passenger side dashpanel in the engine compartment. Refer to ElectronicControl Modules for the procedures.

(7) Reinstall the coolant reserve/overflow bottle tothe passenger side inner fender shield. Refer to Cool-ing for the procedures.

(8) If the vehicle is equipped with the manual tem-perature control system, connect the HVAC systemvacuum supply line connector to the tee fitting nearthe heater core tubes.

(9) Unclamp/unplug the heater core hoses andtubes. Connect the heater hoses to the heater coretubes and fill the engine cooling system. Refer toCooling for the procedures.

(10) Unplug or remove the tape from the suctionline and the evaporator outlet tube fittings. Connectthe suction line to the evaporator outlet tube.Tighten retaining nut to 28 N·m (250 in. lbs.).

(11) Unplug or remove the tape from the liquidline and the evaporator inlet tube fittings. Connectthe liquid line to the evaporator inlet tube. Tightenretaining nut to 28 N·m (250 in. lbs.).

(12) Evacuate the refrigerant system. (Refer to 24- HEATING & AIR CONDITIONING/PLUMBING -STANDARD PROCEDURE - REFRIGERANT SYS-TEM EVACUATE)

(13) Charge the refrigerant system. (Refer to 24 -HEATING & AIR CONDITIONING/PLUMBING -STANDARD PROCEDURE - REFRIGERANT SYS-TEM CHARGE)


(15) Connect the battery negative cable.(16) Start the engine and check for proper opera-

tion of the heating and air conditioning systems.

Fig. 19 BLEND DOOR SUB-ASSEMBLY (AZC)1 - PASSENGER SIDE BLEND DOOR2 - BLEND DOOR SUB-ASSEMBLY3 - DOOR PIVOT SHAFT BUSHING4 - DOOR SHAFT LEVER5 - DRIVER SIDE BLEND DOOR



BLEND DOOR

REMOVAL


(1) Remove and disassemble the HVAC housing.(Refer to 24 - HEATING & AIR CONDITIONING/DISTRIBUTION/HVAC HOUSING - REMOVAL)(Refer to 24 - HEATING & AIR CONDITIONING/DISTRIBUTION/HVAC HOUSING - DISASSEMBLY)

(2) Remove evaporator from lower case to easeaccess to plastic door shaft bushing.

(3) Pinch the retention tabs holding the blend doorpivot shaft to the case. The 3 plastic tabs, located onthe inside of the case, are part of the shaft retainer.

(4) Remove door(s).

INSTALLATION(1) Install the blend door(s) by snapping the pivot

shaft into the HVAC case.(2) Install the evaporator in the lower case.(3) Reassemble the HVAC housing and install in

the vehicle. (Refer to 24 - HEATING & AIR CONDI-TIONING/DISTRIBUTION/HVAC HOUSING -ASSEMBLY) (Refer to 24 - HEATING & AIR CON-DITIONING/DISTRIBUTION/HVAC HOUSING -INSTALLATION)

NOTE: The blend door sub-assembly is attached tothe housing with 2 screws, and may be removed forservice (Fig. 20).

MODE DOOR

REMOVAL - PANEL OUTLET DOOR



Fig. 20 BLEND DOOR SUB-ASSEMBLY1 - PASSENGER SIDE BLEND DOOR2 - BLEND DOOR SUB-ASSEMBLY3 - DOOR PIVOT SHAFT BUSHING4 - DOOR SHAFT LEVER5 - DRIVER SIDE BLEND DOOR


(2) Pinch the retention tabs holding the panel out-let door pivot shaft to the case. The 3 plastic tabs,located on the inside of the case, are part of the shaftretainer (Fig. 21).

(3) Using a trim stick or another suitable wideflat-bladed tool, gently pry the panel outlet door pivotshaft retainer from the pivot shaft.

(4) Remove the panel outlet door from the HVAChousing.

REMOVAL - HEAT/DEFROST DOOR



(2) Remove the evaporator, and styrofoam trayfrom the lower case.

(3) Place the HVAC housing upside down on awork bench.

(4) Unscrew and remove the 2 floor heat ducts.(5) Unsnap and remove the duct adapter from the

bottom of the heat/defrost door sub-assembly (Fig.22).

(6) Gently pry the metal linkage from the heat/de-frost door lever.

(7) Remove the heat/defrost door sub-assembly,which is attached to the housing with 4 screws (Fig.23).

(8) Pinch the retention tabs holding the heat/de-frost door pivot shaft lever to the case. The 3 plastictabs, located on the inside of the case, are part of theshaft retainer.

(9) Remove the heat/defrost door (Fig. 24).

Fig. 21 PANEL OUTLET DOOR1 - PANEL/OUTLET DOOR2 - DOOR SHAFT3 - FOAM SEAL(SPLIT)4 - LOWER HOUSING5 - PANEL OUTLET DOOR LEVER6 - LEVER

Fig. 22 HEAT/DEFROST DOOR DUCTS, ANDADAPTER

1 - FLOOR DUCT ADAPTER2 - HEAT/DEFROST DOOR SUB-ASSEMBLY3 - DOOR LEVERS4 - LOWER HOUSING5 - FLOOR DUCTS6 - LINKAGE7 - RETAINING TABS


MODE DOOR (Continued)

REMOVAL - PANEL/DEFROST DOOR


(1) Remove and disassemble the HVAC housing.See HVAC Housing in this group for the procedures.

(2) Pinch the retention tabs holding the panel/de-frost door pivot shaft to the case. The 3 plastic tabs,located on the inside of the case, are part of the shaftretainer (Fig. 25).

(3) Using a trim stick or another suitable wideflat-bladed tool, gently pry the panel/defrost doorpivot shaft retainer from the pivot shaft.

(4) Remove the panel/defrost door from the HVAChousing.

Fig. 23 HEAT/DEFROST DOOR SUB-ASSEMBLYREMOVAL

1 - HEAT/DEFROST DOOR SUB-ASSEMBLY2 - LEVERS3 - LOWER HOUSING4 - SCREWS5 - LINKAGE

Fig. 24 HEAT/DEFROST DOOR REMOVAL1 - HEAT/DEFROST DOOR2 - LOWER HOUSING3 - HEAT/DEFROST DOOR SUB-ASSEMBLY4 - FLOOR DUCTS5 - DOOR LEVER

Fig. 25 PANEL/DEFROST DOOR1 - UPPER HOUSING2 - LEVER3 - PANEL/DEFROST MODE DOOR



INSTALLATION - PANEL OUTLET DOOR(1) Snap the panel outlet door pivot shaft retainer

on the pivot shaft.(2) Attach the panel outlet door pivot shaft to the

HVAC case.(3) Reassemble the HVAC housing and install in


INSTALLATION - HEAT/DEFROST DOOR(1) Install the heat/defrost door by snapping the

heat/defrost door pivot shaft into the HVAC case.(2) Install the heat/defrost door sub-assembly and

tighten the mounting screws to 2.2 N·m (20 in. lbs.).(3) Attach the metal linkage to the heat/defrost

door lever.(4) Snap the duct adapter to the bottom of the

heat/defrost door sub-assembly.(5) Install the 2 floor heat ducts and tighten the

mounting screws to 2.2 N·m (20 in. lbs.)..(6) Install the evaporator, and styrofoam tray in

the lower case.(7) Reassemble the HVAC housing and install in


INSTALLATION - PANEL/DEFROST DOOR(1) Snap the panel/defrost door pivot shaft retainer

on the pivot shaft.(2) Attach the panel/defrost door pivot shaft to the

HVAC case.(3) Reassemble the HVAC housing and install in


RECIRCULATION DOOR

REMOVAL



(2) Place the HVAC housing right side up on thework bench.

(3) Unplug the wire/vacuum connector from therecirculation door actuator.

(4) Remove the 2 screws fastening the recircula-tion door sub-assembly to the main housing (Fig. 26).

Fig. 26 RECIRCULATION DOOR HOUSING1 - RECIRCULATION DOOR HOUSING2 - ATTACHING SCREWS



(5) Raise the front of the door sub-assembly whilereleasing the 2 tabs holding the rear to the mainhousing, and remove the recirculation door housing.

(6) Remove the electric/vacuum actuator from therecirculation door sub-assembly and set aside.

(7) Pinch the retention tabs holding the recircula-tion door pivot shaft to the case. The 3 plastic tabs,located on the inside of the case, are part of the shaftretainer.

(8) Remove the recirculation door from the recircu-lation air door housing.

INSTALLATION(1) Install the recirculation door in the recircula-

tion air door housing by snapping the pivot shaftretention tabs into the case.

(2) Install the electric/vacuum actuator on therecirculation door sub-assembly. Check door for bind-ing after replacement.

(3) Install the recirculation door housing on theHVAC case and tighten the 2 screws to 2.2 N·m (20in. lbs.).

(4) Plug in the wire/vacuum connector to the recir-culation door actuator.



RECIRCULATION DOOR (Continued)

PLUMBING

TABLE OF CONTENTS

page page

PLUMBINGDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . 51OPERATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51WARNING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52CAUTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52DIAGNOSIS AND TESTING . . . . . . . . . . . . . . . . . 53

REFRIGERANT SYSTEM LEAKS . . . . . . . . . . . 53STANDARD PROCEDURE . . . . . . . . . . . . . . . . . . 54

REFRIGERANT SYSTEM SERVICEEQUIPMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . 54REFRIGERANT RECOVERY. . . . . . . . . . . . . . . 55REFRIGERANT SYSTEM EVACUATE . . . . . . . . 55REFRIGERANT SYSTEM CHARGE . . . . . . . . . 55

SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . 56A/C COMPRESSOR

DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . 56OPERATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57DIAGNOSIS AND TESTING . . . . . . . . . . . . . . . . . 57

COMPRESSOR NOISE. . . . . . . . . . . . . . . . . . . 57REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58INSTALLATION. . . . . . . . . . . . . . . . . . . . . . . . . . . 58

A/C CONDENSERDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . 59OPERATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60INSTALLATION. . . . . . . . . . . . . . . . . . . . . . . . . . . 60

A/C DISCHARGE LINEREMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61INSTALLATION. . . . . . . . . . . . . . . . . . . . . . . . . . . 61

LIQUID LINEREMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

INSTALLATION. . . . . . . . . . . . . . . . . . . . . . . . . . . 62SUCTION LINE

REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63INSTALLATION. . . . . . . . . . . . . . . . . . . . . . . . . . . 63

A/C EVAPORATORDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . 63OPERATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64INSTALLATION. . . . . . . . . . . . . . . . . . . . . . . . . . . 65

ACCUMULATORDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . 65OPERATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65INSTALLATION. . . . . . . . . . . . . . . . . . . . . . . . . . . 66

A/C ORIFICE TUBEDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . 67OPERATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

HEATER COREDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . 68OPERATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68INSTALLATION. . . . . . . . . . . . . . . . . . . . . . . . . . . 69

REFRIGERANTDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . 70OPERATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

REFRIGERANT OILDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . 70OPERATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70STANDARD PROCEDURE . . . . . . . . . . . . . . . . . . 71

REFRIGERANT OIL LEVEL. . . . . . . . . . . . . . . . 71

PLUMBING

DESCRIPTION - REFRIGERANT LINEThe refrigerant lines and hoses are used to carry

the refrigerant between the various air conditioningsystem components. A barrier hose design with anylon tube, which is sandwiched between rubber lay-ers, is used for the R-134a air conditioning system onthis vehicle. This nylon tube helps to further containthe R-134a refrigerant, which has a smaller molecu-lar structure than R-12 refrigerant. The ends of therefrigerant hoses are made from lightweight alumi-num or steel, and commonly use braze-less fittings.

Any kinks or sharp bends in the refrigerant plumb-ing will reduce the capacity of the entire air condi-tioning system. Kinks and sharp bends reduce the

flow of refrigerant in the system. A good rule for theflexible hose refrigerant lines is to keep the radius ofall bends at least ten times the diameter of the hose.In addition, the flexible hose refrigerant lines shouldbe routed so they are at least 80 millimeters (3inches) from the exhaust manifold.

OPERATION - REFRIGERANT LINEHigh pressures are produced in the refrigerant sys-

tem when the air conditioning compressor is operat-ing. Extreme care must be exercised to make surethat each of the refrigerant system connections ispressure-tight and leak free. It is a good practice toinspect all flexible hose refrigerant lines at least oncea year to make sure they are in good condition andproperly routed.

WJ PLUMBING 24 - 51

The refrigerant lines and hoses are coupled withother components of the HVAC system with peanut-block style fittings. A stat-O seal type flat steel gas-ket with a captured compressible O-ring, is used tomate plumbing lines with A/C components to ensurethe integrity of the refrigerant system.

The refrigerant lines and hoses cannot be repairedand, if faulty or damaged, they must be replaced.

WARNING

WARNING:THE AIR CONDITIONING SYSTEM CONTAINSREFRIGERANT UNDER HIGH PRESSURE. SEVEREPERSONAL INJURY MAY RESULT FROM IMPROPERSERVICE PROCEDURES. REPAIRS SHOULD ONLYBE PERFORMED BY QUALIFIED SERVICE PERSON-NEL.AVOID BREATHING THE REFRIGERANT ANDREFRIGERANT OIL VAPOR OR MIST. EXPOSUREMAY IRRITATE THE EYES, NOSE, AND/OR THROAT.WEAR EYE PROTECTION WHEN SERVICING THEAIR CONDITIONING REFRIGERANT SYSTEM. SERI-OUS EYE INJURY CAN RESULT FROM DIRECTCONTACT WITH THE REFRIGERANT. IF EYE CON-TACT OCCURS, SEEK MEDICAL ATTENTION IMME-DIATELY.DO NOT EXPOSE THE REFRIGERANT TO OPENFLAME. POISONOUS GAS IS CREATED WHENREFRIGERANT IS BURNED. AN ELECTRONIC LEAKDETECTOR IS RECOMMENDED.IF ACCIDENTAL SYSTEM DISCHARGE OCCURS,VENTILATE THE WORK AREA BEFORE RESUMINGSERVICE. LARGE AMOUNTS OF REFRIGERANTRELEASED IN A CLOSED WORK AREA WILL DIS-PLACE THE OXYGEN AND CAUSE SUFFOCATION.THE EVAPORATION RATE OF R-134a REFRIGER-ANT AT AVERAGE TEMPERATURE AND ALTITUDEIS EXTREMELY HIGH. AS A RESULT, ANYTHINGTHAT COMES IN CONTACT WITH THE REFRIGER-ANT WILL FREEZE. ALWAYS PROTECT THE SKINOR DELICATE OBJECTS FROM DIRECT CONTACTWITH THE REFRIGERANT.THE R-134a SERVICE EQUIPMENT OR THE VEHI-CLE REFRIGERANT SYSTEM SHOULD NOT BEPRESSURE TESTED OR LEAK TESTED WITH COM-PRESSED AIR. SOME MIXTURES OF AIR ANDR-134a HAVE BEEN SHOWN TO BE COMBUSTIBLEAT ELEVATED PRESSURES. THESE MIXTURES AREPOTENTIALLY DANGEROUS, AND MAY RESULT INFIRE OR EXPLOSION CAUSING INJURY OR PROP-ERTY DAMAGE.

CAUTION

CAUTION:Liquid refrigerant is corrosive to metal surfaces.Follow the operating instructions supplied with theservice equipment being used.Never add R-12 to a refrigerant system designed touse R-134a. Damage to the system will result.R-12 refrigerant oil must not be mixed with R-134arefrigerant oil. They are not compatible.Do not use R-12 equipment or parts on the R-134asystem. Damage to the system will result.Do not overcharge the refrigerant system. This willcause excessive compressor head pressure andcan cause noise and system failure.Recover the refrigerant before opening any fittingor connection. Open the fittings with caution, evenafter the system has been discharged. Never openor loosen a connection before recovering the refrig-erant.The refrigerant system must always be evacuatedbefore charging.Do not open the refrigerant system or uncap areplacement component until you are ready to ser-vice the system. This will prevent contamination inthe system.Before disconnecting a component, clean the out-side of the fittings thoroughly to prevent contami-nation from entering the refrigerant system.Immediately after disconnecting a component fromthe refrigerant system, seal the open fittings with acap or plug.Before connecting an open refrigerant fitting, alwaysinstall a new seal or gasket. Coat the fitting and sealwith clean refrigerant oil before connecting.Do not remove the sealing caps from a replacementcomponent until it is to be installed.When installing a refrigerant line, avoid sharp bendsthat may restrict refrigerant flow. Position the refriger-ant lines away from exhaust system components orany sharp edges, which may damage the line.Tighten refrigerant fittings only to the specifiedtorque. The aluminum fittings used in the refrigerantsystem will not tolerate overtightening.When disconnecting a refrigerant fitting, use a wrenchon both halves of the fitting. This will prevent twistingof the refrigerant lines or tubes.Refrigerant oil will absorb moisture from the atmo-sphere if left uncapped. Do not open a container ofrefrigerant oil until you are ready to use it. Replacethe cap on the oil container immediately after using.Store refrigerant oil only in a clean, airtight, and mois-ture-free container.Keep service tools and the work area clean. Contam-ination of the refrigerant system through carelesswork habits must be avoided.

24 - 52 PLUMBING WJ

PLUMBING (Continued)

REFRIGERANT HOSES/LINES/TUBESPRECAUTIONS

Kinks or sharp bends in the refrigerant plumbingwill reduce the capacity of the entire system. Highpressures are produced in the system when it is oper-ating. Extreme care must be exercised to make surethat all refrigerant system connections are pressuretight.

A good rule for the flexible hose refrigerant lines isto keep the radius of all bends at least ten times thediameter of the hose. Sharp bends will reduce theflow of refrigerant. The flexible hose lines should berouted so they are at least 80 millimeters (3 inches)from the exhaust manifold. It is a good practice toinspect all flexible refrigerant system hose lines atleast once a year to make sure they are in good con-dition and properly routed.

There are two types of refrigerant fittings:• All fittings with O-rings need to be coated with

refrigerant oil before installation. Use only O-ringsthat are the correct size and approved for use withR-134a refrigerant. Failure to do so may result in aleak.

• Unified plumbing connections with gaskets can-not be serviced with O-rings. The gaskets are notreusable and new gaskets do not require lubricationbefore installing.

Using the proper tools when making a refrigerantplumbing connection is very important. Impropertools or improper use of the tools can damage therefrigerant fittings. Always use two wrenches whenloosening or tightening tube fittings. Use one wrenchto hold one side of the connection stationary, whileloosening or tightening the other side of the connec-tion with a second wrench.

The refrigerant must be recovered completely fromthe system before opening any fitting or connection.Open the fittings with caution, even after the refrig-erant has been recovered. If any pressure is noticedas a fitting is loosened, tighten the fitting andrecover the refrigerant from the system again.

Do not discharge refrigerant into the atmosphere.Use an R-134a refrigerant recovery/recycling devicethat meets SAE Standard J2210.

The refrigerant system will remain chemically sta-ble as long as pure, moisture-free R-134a refrigerantand refrigerant oil is used. Dirt, moisture, or air canupset this chemical stability. Operational troubles orserious damage can occur if foreign material ispresent in the refrigerant system.

When it is necessary to open the refrigerant sys-tem, have everything needed to service the systemready. The refrigerant system should not be left opento the atmosphere any longer than necessary. Cap orplug all lines and fittings as soon as they are openedto prevent the entrance of dirt and moisture. All lines

and components in parts stock should be capped orsealed until they are to be installed.

All tools, including the refrigerant recycling equip-ment, the manifold gauge set, and test hoses shouldbe kept clean and dry. All tools and equipment mustbe designed for R-134a refrigerant.

DIAGNOSIS AND TESTING - REFRIGERANTSYSTEM LEAKS

WARNING: REVIEW THE WARNINGS AND CAU-TIONS IN THE FRONT OF THIS SECTION BEFOREPERFORMING THE FOLLOWING OPERATION.(Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - WARNING) (Refer to 24 - HEATING &AIR CONDITIONING/PLUMBING - CAUTION)

If the air conditioning system is not cooling prop-erly, determine if the refrigerant system is fully-charged. (Refer to 24 - HEATING & AIRCONDITIONING - DIAGNOSIS AND TESTING -A/C PERFORMANCE)

An electronic leak detector designed for R-134arefrigerant is recommended for locating and confirm-ing refrigerant system leaks. Refer to the operatinginstructions supplied by the equipment manufacturerfor proper care and use of this equipment.

An oily residue on or near refrigerant system lines,connector fittings, components, or component sealscan indicate the general location of a possible refrig-erant leak. However, the exact leak location shouldbe confirmed with an electronic leak detector prior tocomponent repair or replacement.

To detect a leak in the refrigerant system, performone of the following procedures:

SYSTEM EMPTY(1) Evacuate the refrigerant system. (Refer to 24 -

HEATING & AIR CONDITIONING/PLUMBING -STANDARD PROCEDURE - REFRIGERANT SYS-TEM EVACUATE)

(2) Connect and dispense 0.283 kilograms (0.625pounds or 10 ounces) of R-134a refrigerant into theevacuated refrigerant system. (Refer to 24 - HEAT-ING & AIR CONDITIONING/PLUMBING - STAN-DARD PROCEDURE - REFRIGERANT SYSTEMCHARGE)

(3) Position the vehicle in a wind-free work area.This will aid in detecting small leaks.

(4) With the engine not running, use a electronicR-134a leak detector and search for leaks. BecauseR-134a refrigerant is heavier than air, the leak detec-tor probe should be moved slowly along the bottomside of all refrigerant lines, connector fittings andcomponents.

WJ PLUMBING 24 - 53


(5) To inspect the evaporator coil for leaks, insertthe electronic leak detector probe into the centerinstrument panel outlet. Set the blower motor switchto the lowest speed position, the A/C button in theOn position, and select the Recirculation Mode.

SYSTEM LOW(1) Position the vehicle in a wind-free work area.

This will aid in detecting small leaks.(2) Bring the refrigerant system up to operating

temperature and pressure. This is done by allowingthe engine to run with the air conditioning systemturned on for five minutes.

(3) With the engine not running, use a electronicR-134a leak detector and search for leaks. BecauseR-134a refrigerant is heavier than air, the leak detec-tor probe should be moved slowly along the bottomside of all refrigerant lines, connector fittings andcomponents.

(4) To inspect the evaporator coil for leaks, insertthe electronic leak detector probe into the centerinstrument panel outlet. Set the blower motor switchto the lowest speed position, the A/C button in theOn position, and select the Recirculation Mode.

STANDARD PROCEDURE - REFRIGERANTSYSTEM SERVICE EQUIPMENT

WARNING: EYE PROTECTION MUST BE WORNWHEN SERVICING AN AIR CONDITIONING REFRIG-ERANT SYSTEM. TURN OFF (ROTATE CLOCKWISE)ALL VALVES ON THE EQUIPMENT BEING USED,BEFORE CONNECTING TO OR DISCONNECTINGFROM THE REFRIGERANT SYSTEM. FAILURE TOOBSERVE THESE WARNINGS MAY RESULT IN PER-SONAL INJURY.


When servicing the air conditioning system, aR-134a refrigerant recovery/recycling/charging sta-tion that meets SAE Standard J2210 must be used.Contact an automotive service equipment supplier forrefrigerant recovery/recycling/charging equipment.Refer to the operating instructions supplied by theequipment manufacturer for proper care and use ofthis equipment.

A manifold gauge set may be needed with somerecovery/recycling/charging equipment (Fig. 1). Theservice hoses on the gauge set being used shouldhave manual (turn wheel), or automatic back-flow

valves at the service port connector ends. This willprevent refrigerant from being released into theatmosphere.

MANIFOLD GAUGE SET CONNECTIONS

CAUTION: Do not use an R-12 manifold gauge seton an R-134a system. The refrigerants are not com-patible and system damage will result.

LOW PRESSURE GAUGE HOSE The low pressurehose (Blue with Black stripe) attaches to the suctionservice port. This port is located on the suction linebetween the accumulator outlet and the compressor.

HIGH PRESSURE GAUGE HOSE The high pres-sure hose (Red with Black stripe) attaches to the dis-charge service port. This port is located on thedischarge line between the compressor and the con-denser inlet.

RECOVERY/RECYCLING/EVACUATION/CHARG-ING HOSE The center manifold hose (Yellow, orWhite, with Black stripe) is used to recover, evacu-ate, and charge the refrigerant system. When the lowor high pressure valves on the manifold gauge setare opened, the refrigerant in the system will escapethrough this hose.

Fig. 1 MANIFOLD GAUGE SET - TYPICAL1 - HIGH PRESSURE GAUGE2 - VALVE3 - VACUUM/REFRIGERANT HOSE (YELLOW W/ BLACKSTRIPE)4 - HIGH PRESSURE HOSE (RED W/ BLACK STRIPE)5 - LOW PRESSURE HOSE (BLUE W/ BLACK STRIPE)6 - VALVE7 - LOW PRESSURE GAUGE

24 - 54 PLUMBING WJ


STANDARD PROCEDURE - REFRIGERANTRECOVERY


A R-134a refrigerant recovery/recycling/chargingstation that meets SAE Standard J2210 must beused to recover the refrigerant from an R-134a refrig-erant system. Refer to the operating instructions sup-plied by the equipment manufacturer for the propercare and use of this equipment.

STANDARD PROCEDURE - REFRIGERANTSYSTEM EVACUATE


If the refrigerant system has been open to theatmosphere, it must be evacuated before the systemcan be charged. If moisture and air enters the systemand becomes mixed with the refrigerant, the com-pressor head pressure will rise above acceptableoperating levels. This will reduce the performance ofthe air conditioner and damage the compressor.Evacuating the refrigerant system will remove theair and boil the moisture out of the system at nearroom temperature. To evacuate the refrigerant sys-tem, use the following procedure:

(1) Connect a R-134a refrigerant recovery/recy-cling/charging station that meets SAE StandardJ2210 and a manifold gauge set to the refrigerantsystem of the vehicle.

(2) Open the low and high side valves and startthe charging station vacuum pump. When the suc-tion gauge reads 88 kPa (26 in. Hg.) vacuum orgreater, close all of the valves and turn off the vac-uum pump.

(a) If the refrigerant system fails to reach thespecified vacuum, the system has a leak that mustbe corrected. (Refer to 24 - HEATING & AIR CON-DITIONING/PLUMBING - DIAGNOSIS ANDTESTING - REFRIGERANT SYSTEM LEAKS)

(b) If the refrigerant system maintains the spec-ified vacuum for five minutes, restart the vacuumpump, open the suction and discharge valves andevacuate the system for an additional ten minutes.

(3) Close all of the valves, and turn off the charg-ing station vacuum pump.

(4) The refrigerant system is now ready to becharged with R-134a refrigerant. (Refer to 24 -HEATING & AIR CONDITIONING/PLUMBING -STANDARD PROCEDURE - REFRIGERANT SYS-TEM CHARGE)

STANDARD PROCEDURE - REFRIGERANTSYSTEM CHARGE


After the refrigerant system has been tested forleaks and evacuated, a refrigerant charge can beinjected into the system. (Refer to 24 - HEATING &AIR CONDITIONING/PLUMBING - SPECIFICA-TIONS - CHARGE CAPACITY)

A R-134a refrigerant recovery/recycling/chargingstation that meets SAE Standard J2210 must beused to charge the refrigerant system with R-134arefrigerant. Refer to the operating instructions sup-plied by the equipment manufacturer for proper careand use of this equipment.

PARTIAL CHARGE METHOD


The partial charge method is used to add a partialcharge to a refrigerant system that is low on refrig-erant. To perform this procedure the evaporator inletand outlet tube temperatures are measured. Thetemperature difference is measured with a tempera-ture meter with one or two clamp-on thermocoupleprobes. The difference between the evaporator inletand outlet tube temperatures will determine theamount of refrigerant needed.

Before adding a partial refrigerant charge, checkfor refrigerant system leaks. (Refer to 24 - HEATING& AIR CONDITIONING/PLUMBING - DIAGNOSISAND TESTING - REFRIGERANT SYSTEM LEAKS)If a leak is found, make the necessary repairs beforeattempting a full or partial refrigerant charge.

(1) Attach a manifold gauge set to the refrigerantsystem service ports.

WJ PLUMBING 24 - 55


(2) Attach the two clamp-on thermocouple probesto the inlet and outlet tubes of the evaporator coil.

• If a single thermocouple probe is used, attachthe probe to the evaporator inlet tube just before thecollar of the refrigerant line connector fitting. Theprobe must make contact with the bottom surface ofthe evaporator inlet tube.

• If dual thermocouple probes are used, attachprobe 1 to the evaporator inlet tube, and probe 2 tothe evaporator outlet tube. Attach both probes to theevaporator tubes just before the collar of the refrig-erant line connector fittings. The probes must makecontact with the bottom surfaces of the evaporatorinlet and outlet tubes.

(3) Open all of the windows or doors of the passen-ger compartment.

(4) Set the A/C button on the A/C Heater controlsto the on position, the temperature control knob inthe full cool position, select Recirculation Mode, andplace the blower motor switch in the highest speedposition.

(5) Start the engine and hold the engine idle speedat 1,000 rpm. Allow the engine to warm up to normaloperating temperature.

(6) The compressor clutch may cycle, dependingupon ambient temperature, humidity, and the refrig-erant system charge level. If the compressor clutchcycles, unplug the wire harness connector from thelow pressure cycling clutch switch on the accumula-tor. Install a jumper wire between the two cavities ofthe switch wire harness connector.

(7) Hold the engine idle speed at 1,000 rpm.(8) Allow three to five minutes for the refrigerant

system to stabilize, then record the temperatures ofthe evaporator inlet and outlet tubes.

• If a single probe is used, record the temperatureof the evaporator inlet tube. Then remove the probefrom the inlet tube and attach it to the evaporatoroutlet tube just before the collar of the refrigerantline connector fitting. The probe must make contactwith the bottom surface of the evaporator outlet tube.Allow the thermocouple and meter time to stabilize,then record the temperature of the evaporator outlettube. Subtract the inlet tube temperature readingfrom the outlet tube temperature reading.

• If dual probes are used, record the temperaturesof both the evaporator inlet and outlet tubes. Thensubtract the inlet tube temperature reading from theoutlet tube temperature reading.

(9) If the measured temperature differential ishigher than 22° C to 26° C (40° F to 47° F), add 0.4kilograms (14 ounces) of refrigerant.

(10) Allow three to five minutes for the refrigerantsystem to stabilize, then take a second set of thermo-couple measurements. Record the temperature differ-ence to determine if an additional charge is required.

(11) Record the compressor discharge pressure. Ifthe reading is higher than the pressure shown in theCompressor Discharge Pressure Chart, the systemcould be overcharged. If the reading is equal to, orlower, than the pressure shown in the chart, continuewith this procedure.

Compressor Discharge Pressure Chart

AmbientTemperature

16°C(60°F)

21°C(70°F)

27°C(80°F)

32°C(90°F)

38°C(100°F)

43°C(110°F)

CompressorDischargePressure

1515 kPa(220 psi)

1655 kPa(240 psi)

1790 kPa(260psi)

2070 kPa(300 psi)

2345 kPa(340 psi)

2690 kPa(390 psi)

(12) EXAMPLE: The ambient temperature is 21°C (70° F). The evaporator inlet tube temperature is12° C (54° F) and the evaporator outlet tube temper-ature is 10° C (50° F). Subtract the inlet tube tem-perature from the outlet tube temperature. Thedifference is -2° C (-4° F). With a -2° C (-4° F) tem-perature differential at 21° C (70° F) ambient tem-perature, the system is fully charged.

(13) Add enough refrigerant to bring the refriger-ant system up to a full charge.

(14) Remove the jumper wire from the low pres-sure cycling clutch switch wire harness connectorand plug the connector back into the switch.

SPECIFICATIONS

CHARGE CAPACITYThe R-134a refrigerant system charge capacity for

this vehicle is 0.680 kilograms (1.50 pounds/24 ounc-es).

A/C COMPRESSOR

DESCRIPTION - A/C COMPRESSORThe air conditioning system uses a Nippondenso

10PA17 ten cylinder, double-acting swash plate-typecompressor on all models. This compressor has afixed displacement of 170 cubic centimeters (10.374

24 - 56 PLUMBING WJ


cubic inches), and has both the suction and dischargeports located on the cylinder head. A label identifyingthe use of R-134a refrigerant is located on the com-pressor.

DESCRIPTION - HIGH PRESSURE RELIEFVALVE

A high pressure relief valve is located on the com-pressor manifold, which is on the side of the com-pressor. This mechanical valve is designed to ventrefrigerant from the system to protect against dam-age to the compressor and other system components,caused by condenser air flow restriction or an over-charge of refrigerant.

OPERATION - A/C COMPRESSORThe compressor is driven by the engine through an

electric clutch, drive pulley and belt arrangement.The compressor is lubricated by refrigerant oil that iscirculated throughout the refrigerant system with therefrigerant.

The compressor draws in low-pressure refrigerantvapor from the evaporator through its suction port. Itthen compresses the refrigerant into a high-pressure,high-temperature refrigerant vapor, which is thenpumped to the condenser through the compressor dis-charge port.

The compressor cannot be repaired. If faulty ordamaged, the entire compressor assembly must bereplaced. The compressor clutch, pulley, and coil, areavailable for service.

OPERATION - HIGH PRESSURE RELIEF VALVEThe high pressure relief valve vents the system

when a discharge pressure of 3445 to 4135 kPa (500to 600 psi) or above is reached. The valve closeswhen a minimum discharge pressure of 2756 kPa(400 psi) is reached.

The high pressure relief valve vents only enoughrefrigerant to reduce the system pressure, and thenre-seats itself. The majority of the refrigerant is con-served in the system. If the valve vents refrigerant, itdoes not mean that the valve is faulty.

The high pressure relief valve is a factory-cali-brated unit. The valve cannot be adjusted orrepaired, and must not be removed or otherwise dis-turbed. The valve is only serviced as a part of thecompressor assembly.

DIAGNOSIS AND TESTING - COMPRESSORNOISE

When investigating an air conditioning relatednoise, you must first know the conditions underwhich the noise occurs. These conditions include:weather, vehicle speed, transmission in gear or neu-tral, engine speed, engine temperature, and any

other special conditions. Noises that develop duringair conditioning operation can often be misleading.For example: What sounds like a failed front bearingor connecting rod, may be caused by loose bolts, nuts,mounting brackets, or a loose compressor clutchassembly.

Drive belts are speed sensitive. At different enginespeeds and depending upon belt tension, belts candevelop noises that are mistaken for a compressornoise. Improper belt tension can cause a misleadingnoise when the compressor clutch is engaged, whichmay not occur when the compressor clutch is disen-gaged. Check the serpentine drive belt condition andtension as described in Cooling before beginning thisprocedure.

(1) Select a quiet area for testing. Duplicate thecomplaint conditions as much as possible. Switch thecompressor on and off several times to clearly iden-tify the compressor noise. Listen to the compressorwhile the clutch is engaged and disengaged. Probethe compressor with an engine stethoscope or a longscrewdriver with the handle held to your ear to bet-ter localize the source of the noise.

(2) Loosen all of the compressor mounting hard-ware and retighten. Tighten the compressor clutchmounting nut. Be certain that the clutch coil ismounted securely to the compressor, and that theclutch plate and pulley are properly aligned and havethe correct air gap. (Refer to 24 - HEATING & AIRCONDITIONING/CONTROLS/A/C COMPRESSORCLUTCH - INSTALLATION)

(3) To duplicate a high-ambient temperature condi-tion (high head pressure), restrict the air flowthrough the condenser. Install a manifold gauge setto be certain that the discharge pressure does notexceed 2760 kPa (400 psi).

(4) Check the refrigerant system plumbing forincorrect routing, rubbing or interference, which cancause unusual noises. Also check the refrigerant linesfor kinks or sharp bends that will restrict refrigerantflow, which can cause noises. (Refer to 24 - HEAT-ING & AIR CONDITIONING/PLUMBING - CAU-TION - REFRIGERANT HOSES/LINES/TUBESPRECAUTIONS)

(5) If the noise is from opening and closing of thehigh pressure relief valve, reclaim, evacuate, andrecharge the refrigerant system. (Refer to 24 - HEAT-ING & AIR CONDITIONING/PLUMBING - STAN-DARD PROCEDURE - REFRIGERANT RECOVERY)(Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - STANDARD PROCEDURE - REFRIG-ERANT SYSTEM EVACUATE) (Refer to 24 -HEATING & AIR CONDITIONING/PLUMBING -STANDARD PROCEDURE - REFRIGERANT SYS-TEM CHARGE)If the high pressure relief valve stilldoes not seat properly, replace the a/c compressor.

WJ PLUMBING 24 - 57

A/C COMPRESSOR (Continued)

(Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING/A/C COMPRESSOR - REMOVAL)

(6) If the noise is from liquid slugging on the suc-tion line, replace the accumulator. (Refer to 24 -HEATING & AIR CONDITIONING/PLUMBING/AC-CUMULATOR - REMOVAL) Check the refrigerant oillevel and the refrigerant system charge. (Refer to 24- HEATING & AIR CONDITIONING/PLUMBING/REFRIGERANT OIL - STANDARD PROCEDURE)(Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - SPECIFICATIONS - CHARGECAPACITY) If the liquid slugging condition continuesfollowing accumulator replacement, replace the com-pressor.

(7) If the noise continues, replace the compressorand repeat Step 1.

REMOVALThe compressor may be removed and repositioned

without disconnecting the refrigerant lines or dis-charging the refrigerant system. Discharging is notnecessary if servicing the compressor clutch or clutchcoil, the engine, the cylinder head, or the generator.


(1) Recover the refrigerant from the system. (Referto 24 - HEATING & AIR CONDITIONING/PLUMB-ING - STANDARD PROCEDURE - REFRIGERANTRECOVERY)


(3) Remove the serpentine drive belt. Refer toCooling for the procedures.

(4) Unplug the compressor clutch coil wire harnessconnector.

(5) Remove the (2) refrigerant line retaining boltsthat secure the suction line and discharge line to thecompressor. Install plugs in, or tape over all of theopened refrigerant fittings.

(6) Remove the bolts that secure the compressor(Fig. 2) or (Fig. 3) and (Fig. 4).

(7) Remove the compressor.

INSTALLATION




Fig. 2 COMPRESSOR REMOVE/INSTALL - 4.0LENGINE

1 - POWER STEERING PUMP MOUNTING BRACKET2 - BOLT3 - BRACE4 - BOLT5 - BOLT6 - A/C COMPRESSOR7 - BOLT

24 - 58 PLUMBING WJ


NOTE: If a replacement compressor is beinginstalled, be certain to check the refrigerant oillevel. (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING/REFRIGERANT OIL - STANDARD PRO-CEDURE) Use only refrigerant oil of the typerecommended for the compressor in the vehicle.(Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING/REFRIGERANT OIL - DESCRIPTION)

(1) Install the compressor. Tighten the 4.0Lmounting bolts fastening the compressor to the blockto 45-65 N·m (35-50 ft. lbs.). Tighten the mountingbolts holding the rear brace to the compressor andblock to 40-55 N·m (30-40 ft. lbs.). Tighten the 4.7Lcompressor front mounting screws to 45-65 N·m(35-50 ft. lbs.), and the rear mounting screws to35-45 N·m (25-35 ft. lbs.).

(2) Remove the tape or plugs from all of theopened refrigerant line fittings. Install the suctionline and discharge line fittings to the manifold on thecompressor. Tighten the mounting bolts to 25.4 N·m(225 in. lbs.).

(3) Install the serpentine drive belt. Refer to Cool-ing for the procedures.

(4) Plug in the compressor clutch coil wire harnessconnector.

(5) Connect the battery negative cable.(6) Evacuate the refrigerant system. (Refer to 24 -



A/C CONDENSER

DESCRIPTIONThe condenser is located in the air flow in front of

the engine cooling radiator. The condenser is a heatexchanger that allows the high-pressure refrigerantgas being discharged by the compressor to give up itsheat to the air passing over the condenser fins.

OPERATIONWhen the refrigerant gas gives up its heat, it con-

denses. When the refrigerant leaves the condenser, ithas become a high-pressure liquid refrigerant. Thevolume of air flowing over the condenser fins is crit-ical to the proper cooling performance of the air con-ditioning system. Therefore, it is important thatthere are no objects placed in front of the radiatorgrille openings in the front of the vehicle or foreignmaterial on the condenser fins that might obstructproper air flow. Also, any factory-installed air seals or

Fig. 3 COMPRESSOR REMOVE/INSTALL - V8ENGINE - LEFT VIEW

1 - BOLT2 - A/C COMPRESSOR

Fig. 4 COMPRESSOR REMOVE/INSTALL - V8ENGINE - RIGHT VIEW

1 - BOLT2 - A/C COMPRESSOR3 - BOLT

WJ PLUMBING 24 - 59


shrouds must be properly reinstalled following radia-tor or condenser service.

The condenser cannot be repaired and, if faulty ordamaged, it must be replaced.

REMOVAL


WARNING: REVIEW THE WARNINGS AND CAU-TIONS IN THE FRONT OF THIS GROUP BEFOREPERFORMING THE FOLLOWING OPERATION.

CAUTION: Before removing the condenser, note thelocation of each of the radiator and condenser airseals. These seals are used to direct air through thecondenser and radiator. The air seals must be rein-stalled in their proper locations in order for the airconditioning and engine cooling systems to per-form as designed.



(3) Remove the screws attaching the grille andheadlamp mounting module to the upper crossmem-ber of the vehicle. Refer to Body for this and furthersteps in the procedure.

(4) Remove the headlamps from their mounts.(5) Remove the nuts that secure the hood latch

and brace to the upper crossmember.(6) The radiator upper crossmember can be

adjusted left or right through the use of its slottedmounting holes. Before removal, mark the originalposition of the crossmember.

(7) Remove the bolts that secure the radiator tothe upper crossmember and set it aside (Fig. 5).

(8) Remove the engine air filter inlet duct securedat the headlamp mounting module.

(9) Remove the headlamp mounting module andfront fascia for access to the condenser and fittings.

(10) Disconnect the discharge line and liquid linerefrigerant line fittings from the condenser. Installplugs in, or tape over all of the opened refrigerantline fittings.

(11) Remove the bolts that secure the upper con-denser and transmission cooler.

(12) Carefully lift the condenser out of the vehicle.

INSTALLATION


Any kinks or sharp bends in the refrigerant plumb-ing will reduce the capacity of the entire air condi-tioning system. Kinks and sharp bends reduce theflow of refrigerant in the system. A good rule for theflexible hose refrigerant lines is to keep the radius ofall bends at least ten times the diameter of the hose.In addition, the flexible hose refrigerant lines should

Fig. 5 CONDENSER MOUNTING - TYPICAL1 - CONDENSER-TO-RADIATOR MOUNTING BRACKETS (2)2 - UPPER CROSSMEMBER3 - FAN SHROUD4 - ALIGNMENT TABS5 - RADIATOR6 - ALIGNMENT DOWELS (2)7 - RUBBER ISOLATORS (2)8 - RUBBER GROMMETS (2)9 - LOWER CROSSMEMBER10 - CONDENSER

24 - 60 PLUMBING WJ

A/C CONDENSER (Continued)

be routed so they are at least 80 millimeters (3inches) from the exhaust manifold.


CAUTION: Before removing the condenser, note thelocation of each of the radiator and condenser airseals. These seals are used to direct air through thecondenser and radiator. The air seals must be rein-stalled in their proper locations in order for the airconditioning and engine cooling systems to per-form as designed.

(1) Carefully position the condenser in the vehicle.(2) Install the bolts that secure the upper con-

denser and transmission cooler.(3) Remove the tape or plugs from the refrigerant

line fittings on the condenser inlet and the dischargeline. Connect the discharge line to the condenserinlet. Tighten the retaining nut to 28 N·m (250 in.lbs.).

(4) Remove the tape or plugs from the refrigerantline fittings on the condenser outlet and the liquidline. Connect the liquid line to the condenser outlet.Tighten the retaining nut to 28 N·m (250 in. lbs.).

(5) Install the headlamp mounting module andfront fascia. Refer to Body for the procedure.

(6) Install the engine air filter inlet duct.(7) Install the bolts that secure the radiator to the

upper crossmember.(8) Install the nuts that secure the hood latch and

brace to the upper crossmember.(9) Install the headlamps in their mounts.(10) Install the screws attaching the grille and

headlamp mounting module to the upper crossmem-ber of the vehicle. Refer to Body for this and furthersteps in the procedure.

(11) Evacuate and Recharge the refrigerant sys-tem. (Refer to 24 - HEATING & AIR CONDITION-ING/PLUMBING - STANDARD PROCEDURE -REFRIGERANT SYSTEM EVACUATE) (Refer to 24 -HEATING & AIR CONDITIONING/PLUMBING -STANDARD PROCEDURE - REFRIGERANT SYS-TEM CHARGE)


NOTE: If the condenser is replaced, add 30 millili-ters (1 fluid ounce) of refrigerant oil to the refriger-ant system. Use only refrigerant oil of the typerecommended for the compressor in the vehicle.

(Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING/REFRIGERANT OIL - DESCRIPTION)

A/C DISCHARGE LINE

REMOVAL


WARNING: REVIEW THE WARNINGS AND CAU-TIONS IN THE FRONT OF THIS GROUP BEFOREPERFORMING THE FOLLOWING OPERATION.



(3) Remove the a/c high pressure switch. (Refer to24 - HEATING & AIR CONDITIONING/CONTROLS/A/C HIGH PRESSURE SWITCH - REMOVAL)

(4) Disconnect the discharge line from the con-denser inlet. Install plugs in, or tape over all of theopened refrigerant line fittings.

(5) Remove the bolt that secures the discharge linefitting to compressor. Install plugs in, or tape over allof the opened refrigerant line fittings.

(6) Remove the discharge line assembly from thevehicle.

INSTALLATION



WJ PLUMBING 24 - 61

A/C CONDENSER (Continued)


(1) Remove the tape or plugs from the dischargeline block fitting and the manifold on the compressor.Install the discharge line block fitting to the manifoldon the compressor. Tighten the mounting bolt to 25.4N·m (225 in. lbs.).

(2) Remove the tape or plugs from the refrigerantline fittings on the condenser inlet and the dischargeline. Connect the discharge line to the condenserinlet. Tighten the retaining nut to 28 N·m (250 in.lbs.).

(3) Install the a/c high pressure switch. (Refer to24 - HEATING & AIR CONDITIONING/CONTROLS/A/C HIGH PRESSURE SWITCH - INSTALLATION)




LIQUID LINE

REMOVAL



(2) Recover the refrigerant from the refrigerantsystem. (Refer to 24 - HEATING & AIR CONDI-TIONING/PLUMBING - STANDARD PROCEDURE)

(3) Unsnap the plastic retainer clips that securethe liquid line to the inner fender shield and thedash panel in the engine compartment.

(4) Disengage the liquid line from the plasticretainer clips.

(5) Disconnect the liquid line from the evaporatorinlet. Install plugs in, or tape over all of the openedrefrigerant line fittings.

(6) Disconnect the liquid line from the condenseroutlet. Install plugs in, or tape over all of the openedrefrigerant line fittings.

(7) Remove the liquid line from the plastic clipsthat secure it to the right inner fender shield.

(8) Remove the liquid line from the vehicle.

INSTALLATION




(1) Remove the tape or plugs from the refrigerantline fittings on the condenser outlet tube and thecondenser end of the liquid line. Connect the liquidline to the condenser outlet. Tighten the retainingnut to 28 N·m (250 in. lbs.).

(2) Remove the tape or plugs from the refrigerantline fittings on the evaporator end of the liquid lineand from the evaporator inlet tube. Connect the liq-uid line to the evaporator outlet. Tighten the retain-ing nut to 28 N·m (250 in. lbs.).

(3) Install the liquid line into the plastic retainerclips that secure it to the inner fender shield and thedash panel and snap the retainer clips closed.




24 - 62 PLUMBING WJ

A/C DISCHARGE LINE (Continued)

SUCTION LINE

REMOVAL - 4.7L


The suction line for 4.7L engine applications is ser-viced as part of the accumulator assembly. (Refer to24 - HEATING & AIR CONDITIONING/PLUMBING/ACCUMULATOR - REMOVAL - 4.7L)

REMOVAL - 4.0L




(3) Release the line retainer from the inner fender.(4) Disconnect the suction line from the accumula-

tor outlet. Install plugs in, or tape over all of theopened refrigerant line fittings.

(5) Remove the bolt that secures the suction linefitting to compressor. Install plugs in, or tape over allof the opened refrigerant line fittings.

(6) Remove the suction line assembly from thevehicle.

INSTALLATION - 4.0L


Any kinks or sharp bends in the refrigerant plumb-ing will reduce the capacity of the entire air condi-tioning system. Kinks and sharp bends reduce theflow of refrigerant in the system. A good rule for theflexible hose refrigerant lines is to keep the radius ofall bends at least ten times the diameter of the hose.In addition, the flexible hose refrigerant lines should

be routed so they are at least 80 millimeters (3inches) from the exhaust manifold.


(1) Secure the suction line in the retainer on theinner fender.

(2) Remove the tape or plugs from the suction lineblock fitting and the manifold on the compressor.Install the suction line block fitting to the manifoldon the compressor. Tighten the mounting bolt to 25.4N·m (225 in. lbs.).

(3) Remove the tape or plugs from the refrigerantline fittings on the accumulator outlet and the suc-tion line. Connect the suction line to the accumulatoroutlet. Tighten the retaining nut to 28 N·m (250 in.lbs.).




A/C EVAPORATOR

DESCRIPTIONThe evaporator coil is located in the HVAC hous-

ing, under the instrument panel. The evaporator coilis positioned in the HVAC housing so that all air thatenters the housing must pass over the fins of theevaporator before it is distributed through the sys-tem ducts and outlets. However, air passing over theevaporator coil fins will only be conditioned when thecompressor is engaged and circulating refrigerantthrough the evaporator coil tubes.

OPERATIONRefrigerant enters the evaporator from the orifice

tube as a low-temperature, low-pressure liquid. Asair flows over the fins of the evaporator, the humidityin the air condenses on the fins, and the heat fromthe air is absorbed by the refrigerant. Heat absorp-tion causes the refrigerant to boil and vaporize. Therefrigerant becomes a low-pressure gas before itleaves the evaporator.

WJ PLUMBING 24 - 63

The evaporator coil cannot be repaired and, iffaulty or damaged, it must be replaced.

REMOVAL

WARNING: ON VEHICLES EQUIPPED WITH AIR-BAGS, DISABLE THE AIRBAG SYSTEM BEFOREATTEMPTING ANY STEERING WHEEL, STEERINGCOLUMN, OR INSTRUMENT PANEL COMPONENTDIAGNOSIS OR SERVICE. DISCONNECT AND ISO-LATE THE BATTERY NEGATIVE (GROUND) CABLE,THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-TEM CAPACITOR TO DISCHARGE BEFORE PER-FORMING FURTHER DIAGNOSIS OR SERVICE. THISIS THE ONLY SURE WAY TO DISABLE THE AIRBAGSYSTEM. FAILURE TO TAKE THE PROPER PRE-CAUTIONS COULD RESULT IN AN ACCIDENTAL

AIRBAG DEPLOYMENT AND POSSIBLE PERSONALINJURY.



(2) Lift the evaporator coil unit out of the lowerhalf of the HVAC housing (Fig. 6).

Fig. 6 UPPER AND LOWER HVAC HOUSING-SEPARATED1 - ELECTRICAL CONNECTORS2 - VACUUM ACTUATOR3 - RECIRCULATION DOOR4 - BLOWER MOTOR RESISTOR/CONTROLLER5 - BLOWER WHEEL6 - EVAPORATOR AND TUBES7 - BLEND DOOR8 - PIVOT SHAFT (MOTOR REMOVED)

9 - PANEL/OUTLET DOOR10 - LOWER HOUSING11 - VACUUM ACTUATORS12 - UPPER HOUSING13 - VACUUM HARNESS14 - HEATER CORE AND TUBES

24 - 64 PLUMBING WJ

A/C EVAPORATOR (Continued)

INSTALLATION




(1) Install the evaporator coil in the bottom half ofthe HVAC housing. Be certain that the evaporatorfoam insulator wrap is reinstalled.

(2) Reassemble the HVAC housing and install inthe vehicle. (Refer to 24 - HEATING & AIR CONDI-TIONING/DISTRIBUTION/HVAC HOUSING -ASSEMBLY) (Refer to 24 - HEATING & AIR CON-DITIONING/DISTRIBUTION/HVAC HOUSING -INSTALLATION)

NOTE: If the evaporator is replaced, add 60 millili-ters (2 fluid ounces) of refrigerant oil to the refrig-erant system.

ACCUMULATOR

DESCRIPTIONThe accumulator is mounted in the engine com-

partment between the evaporator coil outlet tube andthe compressor inlet.

OPERATIONRefrigerant enters the accumulator canister as a

low pressure vapor through the inlet tube. Any liq-uid, oil-laden refrigerant falls to the bottom of thecanister, which acts as a separator. A desiccant bag ismounted inside the accumulator canister to absorbany moisture which may have entered and becometrapped within the refrigerant system (Fig. 7).

REMOVAL - 4.0L



(2) Remove the a/c low pressure switch from theaccumulator. (Refer to 24 - HEATING & AIR CON-DITIONING/CONTROLS/A/C LOW PRESSURESWITCH - REMOVAL)

(3) Recover the refrigerant from the refrigerantsystem. (Refer to 24 - HEATING & AIR CONDI-

Fig. 7 ACCUMULATOR - TYPICAL1 - A/C LOW PRESSURE SWITCH2 - PRESSURE SWITCH FITTING3 - OUTLET TO COMPRESSOR4 - ANTI-SIPHON HOLE5 - DESICCANT BAG6 - OIL RETURN ORIFICE FILTER7 - VAPOR RETURN TUBE8 - ACCUMULATOR DOME9 - O-RING SEAL10 - INLET FROM EVAPORATOR

WJ PLUMBING 24 - 65

A/C EVAPORATOR (Continued)

TIONING/PLUMBING - STANDARD PROCEDURE -REFRIGERANT RECOVERY)

(4) Disconnect the accumulator line from the evap-orator outlet. Install plugs in, or tape over all of theopened refrigerant line fittings.

(5) Remove the nut that secures the suction line tothe accumulator. Install plugs in, or tape over all ofthe opened refrigerant line fittings.

(6) Loosen the screw that clamps the band of theaccumulator support bracket around the accumulator(Fig. 8).

(7) Remove the accumulator from the supportbracket.

REMOVAL - 4.7L


The suction lines from the evaporator outlet tubeto the accumulator, and from the accumulator to thesuction port of the compressor manifold are integral

to the accumulator. If either suction line or the accu-mulator is faulty or damaged, the accumulatorassembly must be replaced.


(2) Remove the a/c low pressure switch from theaccumulator. (Refer to 24 - HEATING & AIR CON-DITIONING/CONTROLS/A/C LOW PRESSURESWITCH - REMOVAL)


(4) Disconnect the suction line refrigerant line fit-ting from the evaporator outlet tube. Install plugs in,or tape over all of the opened refrigerant line fittings.

(5) Remove the bolt that secures the suction lineblock fitting to the manifold on the compressor.Install plugs in, or tape over all of the opened refrig-erant line fittings.

(6) Loosen the screw that clamps the band of theaccumulator support bracket around the accumula-tor.

(7) Remove the accumulator from the supportbracket.

INSTALLATION - 4.0L




(1) Install the accumulator through the band ofthe support bracket. Be certain that the index tab onthe side of the accumulator is aligned with the notchin the support bracket band.

Fig. 8 ACCUMULATOR AND LOW PRESSURESWITCH

1 - SERVICE PORT2 - LOW PRESSURE SWITCH3 - ACCUMULATOR4 - SUPPORT BRACKET

24 - 66 PLUMBING WJ

ACCUMULATOR (Continued)

(2) Tighten the clamp screw in the support bracketband to 12 N·m (105 in. lbs.).

(3) Remove the tape or plugs from the suction linefitting and the accumulator fitting. Install the suc-tion line fitting to the accumulator. Tighten themounting bolt to 28 N·m (250 in. lbs.).

(4) Remove the tape or plugs from the accumulatorline and the evaporator outlet. Install the accumula-tor line to the evaporator. Tighten the retaining nutto 28 N·m (250 in. lbs.).

(5) Install the a/c low pressure switch onto theaccumulator fitting. (Refer to 24 - HEATING & AIRCONDITIONING/CONTROLS/A/C LOW PRESSURESWITCH - INSTALLATION)




NOTE: If the accumulator is replaced, add 120 mil-liliters (4 fluid ounces) of refrigerant oil to therefrigerant system. Use only refrigerant oil of thetype recommended for the compressor in the vehi-cle. (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING/REFRIGERANT OIL - DESCRIPTION)

INSTALLATION - 4.7L


The suction lines from the evaporator outlet tubeto the accumulator, and from the accumulator to thesuction port of the compressor manifold are integralto the accumulator. If either suction line or the accu-mulator is faulty or damaged, the accumulatorassembly must be replaced.



(1) Install the accumulator through the band ofthe support bracket. Be certain that the index tab onthe side of the accumulator is aligned with the notchin the support bracket band.

(2) Tighten the clamp screw in the support bracketband to 12 N·m (105 in. lbs.).

(3) Remove the tape or plugs from the suction lineblock fitting and the manifold on the compressor.Install the suction line block fitting to the manifoldon the compressor. Tighten the mounting bolt to 25.4N·m (225 in. lbs.).

(4) Remove the tape or plugs from the refrigerantline fittings on the suction line and the evaporatoroutlet. Install the suction line to the evaporator.Tighten the retaining nut to 28 N·m (250 in. lbs.).

(5) Install the a/c low pressure switch onto theaccumulator fitting. (Refer to 24 - HEATING & AIRCONDITIONING/CONTROLS/A/C LOW PRESSURESWITCH - INSTALLATION)




NOTE: If the accumulator is replaced, add 120 mil-liliters (4 fluid ounces) of refrigerant oil to therefrigerant system. Use only refrigerant oil of thetype recommended for the compressor in the vehi-cle. (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING/REFRIGERANT OIL - DESCRIPTION)

A/C ORIFICE TUBE

DESCRIPTIONThe fixed orifice tube is installed in the liquid line

between the outlet of the condenser and the inlet ofthe evaporator. The fixed orifice tube is located in theend of the liquid line that is closest to the condenseroutlet tube.

The inlet end of the fixed orifice tube has a nylonmesh filter screen, which filters the refrigerant andhelps to reduce the potential for blockage of the

WJ PLUMBING 24 - 67

ACCUMULATOR (Continued)

metering orifice by refrigerant system contaminants(Fig. 9). The outlet end of the tube has a nylon meshdiffuser screen. The O-rings on the plastic body ofthe fixed orifice tube seal the tube to the inside ofthe liquid line and prevent the refrigerant frombypassing the fixed metering orifice.

OPERATIONThe fixed orifice tube is used to meter the flow of

liquid refrigerant into the evaporator coil. The high-pressure liquid refrigerant from the condenserexpands into a low-pressure liquid as it passesthrough the metering orifice and diffuser screen ofthe fixed orifice tube.

The fixed orifice tube cannot be repaired and, iffaulty or plugged, the liquid line and fixed orificetube unit must be replaced.

REMOVALThe fixed orifice tube is located in the liquid line

near the condenser. The orifice has filter screens onthe inlet and outlet ends of the tube body. If the fixedorifice tube is faulty or plugged, the liquid line unitmust be replaced. (Refer to 24 - HEATING & AIRCONDITIONING/PLUMBING/LIQUID LINE -REMOVAL)

HEATER CORE

DESCRIPTIONThe heater core is located in the HVAC housing,

under the instrument panel. It is a heat exchangermade of rows of tubes and fins.

OPERATIONEngine coolant is circulated through heater hoses

to the heater core at all times. As the coolant flowsthrough the heater core, heat removed from theengine is transferred to the heater core fins and

tubes. Air directed through the heater core picks upthe heat from the heater core fins. The temperaturecontrol door allows control of the heater output airtemperature by controlling how much of the air flow-ing through the HVAC housing is directed throughthe heater core. The blower motor speed controls thevolume of air flowing through the HVAC housing.

The heater core cannot be repaired and, if faulty ordamaged, it must be replaced. Refer to Cooling formore information on the engine cooling system, theengine coolant and the heater hoses.

REMOVAL




(2) Remove the foam gasket surrounding the coretubes.

NOTE: Notice the orientation of the irregularlyshaped gasket on the tubes. The gasket must beplaced correctly to ensure proper sealing againstthe body during reinstallation .

(3) Remove the screws and retainers that securethe heater core and tubes to the HVAC housing (Fig.10).

(4) Remove the mode door actuator if necessary,for clearance to remove the core.

(5) Lift the heater core straight up and out of theHVAC housing (Fig. 11).

Fig. 9 FIXED ORIFICE TUBE - TYPICAL1 - DIFFUSER SCREEN2 - 9O9 RINGS3 - INLET FILTER SCREENS4 - ORIFICE

24 - 68 PLUMBING WJ

A/C ORIFICE TUBE (Continued)

(6) When replacing individual tubes, loosen andremove the round tube-to-core clamp, and pull tubefrom core.

INSTALLATION



High pressures are produced in the refrigerant sys-tem when the air conditioning compressor is operat-ing. Extreme care must be exercised to make surethat each of the refrigerant system connections is

Fig. 11 HEATER CORE AND TUBES1 - ELECTRICAL CONNECTORS2 - EVAPORATOR FITTINGS(CAPPED)3 - ELECTRIC ACTUATOR4 - OUTLET TO DEFROSTER DUCTS5 - ELECTRIC ACTUATOR6 - FLOOR DUCT7 - TO REAR PASSENGER FLOOR AIR DUCTS

8 - FLOOR DUCT9 - HEATER CORE AND TUBES10 - HOUSING DRAIN11 - BLOWER MOTOR RESISTOR/CONTROLLER12 - BLOWER MOTOR13 - GROUND STRAP

Fig. 10 HEATER CORE, TUBES, AND RETAINERS1 - TUBE-TO-CORE CLAMPS2 - GROUND STRAP3 - HVAC HOUSING4 - TUBE RETAINERS AND SCREWS5 - HEATER CORE

WJ PLUMBING 24 - 69

HEATER CORE (Continued)

pressure-tight and leak free. It is a good practice toinspect all flexible hose refrigerant lines at least oncea year to make sure they are in good condition andproperly routed.

(1) When installing individual tubes, insert tubeinto core ensuring that tube O-ring is seated in coreand not pinched. Hold tube in seated position whileinstalling the round tube-to-core clamp (Fig. 12).

NOTE: The round tube-to-heater-core clamp shouldbe left loose enough to turn the tube in the core.Position the core in the housing, and then tightenthe tube-to-heater-core clamp after orienting thetubes to the molded HVAC housing.

(2) Lower the heater core into the HVAC housing.(3) Install the mode door actuator, if removed from

housing for core removal.(4) Position the retainers over the heater core

tubes. Install and tighten the screws that secure theheater core and retainers to the HVAC housing.Tighten the screws to 2.2 N·m (20 in. lbs.).

NOTE: The grounding strap is to be attached to thelower heater core tube retainer.

(5) Reinstall the HVAC housing to the vehicle.(Refer to 24 - HEATING & AIR CONDITIONING/DISTRIBUTION/HVAC HOUSING - INSTALLA-TION)

REFRIGERANT

DESCRIPTIONThe refrigerant used in this air conditioning sys-

tem is a HydroFluoroCarbon (HFC), type R-134a.Unlike R-12, which is a ChloroFluoroCarbon (CFC),R-134a refrigerant does not contain ozone-depletingchlorine. R-134a refrigerant is a non-toxic, non-flam-mable, clear, and colorless liquefied gas.

Even though R-134a does not contain chlorine, itmust be reclaimed and recycled just like CFC-typerefrigerants. This is because R-134a is a greenhousegas and can contribute to global warming.

OPERATIONR-134a refrigerant is not compatible with R-12

refrigerant in an air conditioning system. Even asmall amount of R-12 added to an R-134a refrigerantsystem will cause compressor failure, refrigerant oilsludge or poor air conditioning system performance.In addition, the PolyAlkylene Glycol (PAG) syntheticrefrigerant oils used in an R-134a refrigerant systemare not compatible with the mineral-based refriger-ant oils used in an R-12 refrigerant system.

R-134a refrigerant system service ports, servicetool couplers and refrigerant dispensing bottles haveall been designed with unique fittings to ensure thatan R-134a system is not accidentally contaminatedwith the wrong refrigerant (R-12). There are alsolabels posted in the engine compartment of the vehi-cle and on the compressor identifying to service tech-nicians that the air conditioning system is equippedwith R-134a.

REFRIGERANT OIL

DESCRIPTIONThe refrigerant oil used in R-134a refrigerant sys-

tems is a synthetic-based, PolyAlkylene Glycol (PAG),wax-free lubricant. Mineral-based R-12 refrigerantoils are not compatible with PAG oils, and shouldnever be introduced to an R-134a refrigerant system.

There are different PAG oils available, and eachcontains a different additive package. The 10PA17compressor used in this vehicle is designed to use anND8 PAG refrigerant oil. Use only refrigerant oil ofthis same type to service the refrigerant system.

OPERATIONAfter performing any refrigerant recovery or recy-

cling operation, always replenish the refrigerant sys-tem with the same amount of the recommendedrefrigerant oil as was removed. Too little refrigerantoil can cause compressor damage, and too much canreduce air conditioning system performance.

Fig. 12 HEATER CORE, TUBES, AND O-RINGS1 - HEATER CORE TUBES2 - TUBE-TO-CORE CLAMPS3 - SCREWS4 - O-RINGS5 - HEATER CORE

24 - 70 PLUMBING WJ

HEATER CORE (Continued)

PAG refrigerant oil is much more hygroscopic thanmineral oil, and will absorb any moisture it comesinto contact with, even moisture in the air. The PAGoil container should always be kept tightly cappeduntil it is ready to be used. After use, recap the oilcontainer immediately to prevent moisture contami-nation.

STANDARD PROCEDURE - REFRIGERANT OILLEVEL

When an air conditioning system is assembled atthe factory, all components except the compressor arerefrigerant oil free. After the refrigerant system hasbeen charged and operated, the refrigerant oil in thecompressor is dispersed throughout the refrigerantsystem. The accumulator, evaporator, condenser, andcompressor will each retain a significant amount ofthe needed refrigerant oil.

It is important to have the correct amount of oil inthe refrigerant system. This ensures proper lubrica-tion of the compressor. Too little oil will result indamage to the compressor. Too much oil will reducethe cooling capacity of the air conditioning system.

It will not be necessary to check the oil level in thecompressor or to add oil, unless there has been an oilloss. An oil loss may occur due to a rupture or leakfrom a refrigerant line, a connector fitting, a compo-nent, or a component seal. If a leak occurs, add 30

milliliters (1 fluid ounce) of refrigerant oil to therefrigerant system after the repair has been made.Refrigerant oil loss will be evident at the leak pointby the presence of a wet, shiny surface around theleak.

Refrigerant oil must be added when a accumulator,evaporator coil, or condenser are replaced. See theRefrigerant Oil Capacities chart. When a compressoris replaced, the refrigerant oil must be drained fromthe old compressor and measured. Drain all of therefrigerant oil from the new compressor, then fill thenew compressor with the same amount of refrigerantoil that was drained out of the old compressor.

Refrigerant Oil Capacities

Component ml fl oz

A/C System 170 5.75

Accumulator 110.6 3.75

Condenser 6.5 0.22

Evaporator 62.7 2.12

Compressor

drain and measurethe oil from the oldcompressor - seetext.

WJ PLUMBING 24 - 71

REFRIGERANT OIL (Continued)

24. hvac

Documents

ofunconditioned air

cooled air

air type systems

hvac system operation

blendair system

air conditioner

air flow velocity

system toensure