an ISO 9001:2015 Registered Company

1955-56 Chevrolet Full-Size with 4-Vent Plenum

Evaporator Kit(56156-PCZ)

18865 Goll St. San Antonio, TX 78266 Phone: 800-862-6658

Sales: sales@vintageair.comTech Support: tech@vintageair.com

www.vintageair.com

906156 REV I 05/04/21, PG 1 OF 27

2

www.vintageair.com

906156 REV I 05/04/21, PG 2 OF 27

Cover..................................................................................................................................Table of Contents.................................................................................................................Packing List/Parts Disclaimer..................................................................................................Information Page.................................................................................................................Wiring Notice.......................................................................................................................Engine Compartment Disassembly, Passenger Compartment Disassembly....................................Condenser Assembly Installation, Core Support Modification......................................................Compressor and Brackets, Defrost Duct Installation, Control Panel Conversion.............................Evaporator Installation.......................................................................................................... Evaporator Installation (Cont.).............................................................................................Defrost Duct Installation, Center Vent Installation................................................................... Under Dash Louver Installation, Drain Hose Installation...........................................................Lubricating O-rings, Heater Control Valve Installation.............................................................. A/C Hardline and Hose Installation, Liquid Line and Binary Switch Installation............................. A/C and Heater Hose Routing............................................................................................... Firewall Cover Installation...................................................................................................Wiring Installation.............................................................................................................. Duct Hose Routing.............................................................................................................. Glove Box Installation, Final Steps........................................................................................ Evaporator Hardline Installation........................................................................................... Wiring Diagram..................................................................................................................Gen IV Wiring Connection Instruction...................................................................................Operation of Controls.........................................................................................................Troubleshooting Guide........................................................................................................Troubleshooting Guide (Cont.).............................................................................................Core Support Modification Template......................................................................................Packing List.......................................................................................................................

1 2 3 4 5 6 7 8 91011121314 15161718192021222324252627

Table of Contents

3

www.vintageair.com

906156 REV I 05/04/21, PG 3 OF 27

Packing List: Evaporator Kit (56156-PCZ)

No. 1.2.

Qty.11

Part No.76116078256-PCN

DescriptionGen IV Evaporator Sub Case 4-Vent Plenum with 204 ECUAccessory Kit

** Before beginning installation, open all packages and check contents of shipment. Please report any shortages directly to Vintage Air within 15 days. After 15 days, Vintage Air will not be responsible for missing or damaged items.

NOTE: Images may not depict actual parts and quantities. Refer to packing list for actual parts and quantities.

1

2

Gen IV Evaporator Sub Case 4-Vent Plenum

with 204 ECU761160

Accessory Kit78256-PCN

Passenger SideDriver Side

4

www.vintageair.com

906156 REV I 05/04/21, PG 4 OF 27

Important Notice—Please ReadFor Maximum System Performance, Vintage Air Recommends the Following:

New Vintage Air-Supplied Sanden Compressor: No additional oil needed (Compressor is shipped with proper oil charge).All Other Compressors: Consult manufacturer (Some compressors are shipped dry and will need oil added).

NOTE: Vintage Air systems are designed to operate with R134a refrigerant only. Use of any other refrigerant could damage your A/C system and/or vehicle, and possibly cause a fire, in addition to potentially voiding the warranties of the A/C system and its components.

Refrigerant Capacities:Vintage Air System: 1.8 lbs. (28.8 oz.) or 816 grams of R134a, charged by weight with a quality charging station or scale. NOTE: Use of the proper type and amount of refrigerant is critical to system operation and performance.Other Systems: Consult manufacturer’s guidelines.

Lubricant Capacities:

Safety Switches

Service Info:Protect Your Investment: Prior to assembly, it is critical that the compressor, evaporator, A/C hoses and fittings, hardlines, condenser and receiver/drier remain capped. Removing caps prior to assembly will allow moisture, insects and debris into the components, possibly leading to reduced performance and/or premature failure of your A/C system. This is especially important with the receiver/drier. Additionally, when caps are removed for assembly, BE CAREFUL! Some components are shipped under pressure with dry nitrogen.Evacuate the System for 35-45 Minutes: Ensure that system components (Drier, compressor, evaporator and condenser) are at a temperature of at least 85°F. On a cool day, the components can be heated with a heat gun or by running the engine with the heater on before evacuating. Leak check and charge to specifications.

Your Vintage Air system is equipped with a binary pressure safety switch. A binary switch disengages the compressor clutch in cases of extreme low pressure conditions (refrigerant loss) or excessively high head pressure (406 PSI) to prevent compressor damage or hose rupture. A trinary switch combines Hi/Lo pressure protection with an electric fan operation signal at 254 PSI, and should be substituted for use with electric fans. Compressor safety switches are extremely important since an A/C system relies on refrigerant to circulate lubricant.

Bolts Passing Through Cowl and/or Firewall:To ensure a watertight seal between the passenger compartment and the vehicle exterior, for all bolts passing through the cowl and/or firewall, Vintage Air recommends coating the threads with silicone prior to installation.

Heater Hose (not included with this kit):Heater hose may be purchased from Vintage Air (Part#31800-VUD) or your local parts retailer. Routing and required length will vary based on installer preference.

5

www.vintageair.com

906156 REV I 05/04/21, PG 5 OF 27

Important Wiring Notice—Please Read

Some vehicles may have had some or all of their radio interference capacitors removed. There should be a capacitor found at each of the following locations:

1. On the positive terminal of the ignition coil.2. If there is a generator, on the armature terminal of the generator.3. If there is a generator, on the battery terminal of the voltage regulator.

Most alternators have a capacitor installed internally to eliminate what is called “whining” as the engine is revved. If whining is heard in the radio, or just to be extra cautious, a radio interference capacitor can be added to the battery terminal of the alternator.

It is also important that the battery lead is in good shape and that the ground leads are not compromised. There should be a heavy ground from the battery to the engine block, and additional grounds to the body and chassis.

If these precautions are not observed, it is possible for voltage spikes to be present on the battery leads. These spikes come from ignition systems and charging systems, and from switching some of the vehicle’s other systems on and off. Modern computer-operated equipment can be sensitive to voltage spikes on the power leads, which can cause unexpected resets, strange behavior and/or permanent damage.

Vintage Air strives to harden our products against these types of electrical noise, but there is a point where a vehicle’s electrical system can be degraded so much that nothing can help.

Radio interference capacitors should be available at most auto and truck parts suppliers. They typically are cylindrical in shape, a little over an inch long and a little over a half-inch in diameter, and they have a single lead coming from one end of the cylinder with a terminal on the end of the wire, as well as a mounting clip which is screwed into a good ground on the vehicle. The specific value of the capacitance is not too significant in comparison to ignition capacitors that are matched with the coil to reduce pitting of the points.

Care must be taken, when installing the compressor lead, not to short it to ground. The compressor lead must not be connected to a condenser fan or to any other auxiliary device. Shorting to ground or connecting to a condenser fan or any other auxiliary device may damage wiring or the compressor relay, and/or cause a malfunction.

When installing ground leads on Gen IV systems, the blower control ground and ECU ground must be connected directly to the negative battery post.

For proper system operation, the heater control valve must be connected to the ECU.

•

•

•

6

www.vintageair.com

906156 REV I 05/04/21, PG 6 OF 27

Engine Compartment Disassembly

1.2.3.4.5.

Disconnect battery.Remove battery and battery tray.Remove air cleaner.Drain radiator.Disconnect heater hoses.

NOTE: Before starting the installation, check the function of the vehicle (horn, lights, etc.) for proper operation, and study the instructions, illustrations, & diagrams.Perform the Following:

Figure 1

Passenger Compartment Disassembly

1.

2.3.

4.5.6.7.8.9.

10.11.

Remove the OEM heater assembly by removing the control cables, along with (2) 7/16” nuts on the firewall and (1) under the dash (discard).Remove the heater blower (discard) (See Figure 1, below).Remove the butterfly duct above the kick panel vent, as well as the panel flange (discard). Install the new vent cover as shown in Figure 2, below.Remove the glove box door (retain).Remove the glove box (discard).Remove the original defrost duct from the heater to the windshield (discard).Remove the ash tray (retain).Remove the ash tray slider assembly (retain).Remove the vent and cables from the dash (retain) (See Figure 1, below).Remove the control panel (retain).Remove the passenger side speaker grille (retain) (See Figure 1, below).

Perform the Following:

Figure 2

10

11

14

7

8

5

6

29

3

OEMScrews

7

www.vintageair.com

906156 REV I 05/04/21, PG 7 OF 27

Core Support Modification

Condenser Assembly Installation

1.

2.

3.4.

1.2.

Locate the core support modification template on Page 24, and align the template on the passenger side of the core support panel. Using the template, mark holes and cut a 1 ¼” hole using a hole saw. Drill a 5/16” hole in the noted location (See Figure 3a, below).Install the #6 and #8 condenser hardlines through the 1 ¼” hole. Lubricate a #6 and #8 O-ring as shown in Figure 11, Page 12, and connect the #6 and #8 condenser hardlines to the condenser.Locate the split grommet and install as shown in Figure 3b, below.Install the drier loosely as shown in Figure 3b, below. NOTE: Refrigerant flow follows the arrow on the drier.

Loosen the (6) bolts that secure the radiator to the core support.Slide the condenser assembly into position. The condenser brackets will be held between the radiator and the core support. Secure with the (6) radiator bolts (See Figures 3 and 3b, below). Holding the condenser in position, tighten the (6) radiator bolts.

CORE SUPPORTTEMPLATE

1 ¼”

5/16”

Figure 3

Figure 3a

Figure 3b

OEM Radiator

Vintage AirCondenser

NOTE: #8 (Larger)Fitting is at Top of Radiator.

#8 Condenser Hardline

35018-VCG

#6 Condenser Hardline

35017-VCG

Install (8) #6 x 3/8”Pan Head Screws

Side of CoreSupport

Hole inCore Support

1/4” Nut with Flat Washer

Drier

5/16” Bolts

1/4” x 1” Bolt

Split Grommet

Mount Drier to Inside of Core Support

Through 5/16” Hole

8

www.vintageair.com

906156 REV I 05/04/21, PG 8 OF 27

Defrost Duct Installation1.

2.

Install the defrost ducts with 2” duct hose: 10” (passenger side) and 24” (driver side) (See Figure 4, below, and Figure 15, Page 18).Install the defrost ducts (See Figures 4 and 4a, below). NOTE: The rounded side of the defrost ducts face the passenger compartment.

Compressor and Brackets

Control Panel Conversion

1.

1.

Refer to separate instructions included with the bracket kit to install the compressor bracket.

Locate the control panel conversion kit. Refer to the instructions supplied with the conversion kit to assemble the control panel.

Figure 4

Figure 4a

#8 x 1/2” Pan Head Screw(For 1955 Models

using Existing Holes)

#8 x 1/2” Pan Head Screw(For 1956 Models

using Existing Holes) Seat Bracketin Defrost Hole

Defrost Duct(Rounded Side Out)

Defrost Hole

9

www.vintageair.com

906156 REV I 05/04/21, PG 9 OF 27

Evaporator Installation

1.

2.

3.

4.

5.

On a workbench, install the evaporator rear brackets and the evaporator hardlines with properly lubricated O-rings (See Figure 17, Page 20, and Figure 10, Page 13).Remove the defrost plenum from the evaporator unit by removing (2) 10-32 x 1/2” screws (See Photo 1, below).Lift the evaporator unit up and under the dashboard (See Figure 5, below, and Figure 5a, Page 10). Secure loosely to the firewall from the engine compartment side with (2) 1/4-20 x 1” bolts and washers (See Figure 6, Page 10, and Figure 17, Page 20). NOTE: To ensure proper drainage, it is very important that the evaporator is level, both left-right and fore-aft. Check for level on the flat portions of the case around the drain.Install the front mounting bracket to the evaporator unit using a 1/4-20 x 1/2” button head screw, and tighten as shown in Figure 6, Page 10. Loosely attach the front mounting bracket to the dash with a 1/4-20 x 1” bolt, washer and nut (See Figure 6, Page 10).Verify that the evaporator unit is level and square to the dash, then tighten all mounting bolts. NOTE: Tighten the (2) bolts on the firewall first. Then tighten the front mounting bracket bolt and nut. Tighten the center plenum mounting bolt last.

NOTE: Before starting with the evaporator installation, the defrost plenum must be temporarily removed to provide enough clearance to install the evaporator sub case under the dash. To ensure a watertight seal between the passenger compartment and the vehicle exterior, for all bolts passing through the firewall, Vintage Air recommends coating the threads with silicone prior to installation.

Figure 5

NOTE: Install the evaporator unit from the passenger side floorboard. Rotate the evaporator unit so the lines pass through the opening in the firewall. Lift into place.

Photo 1

Remove (2) 10-32 x 1/2”

Screws

DefrostPlenum

10

www.vintageair.com

906156 REV I 05/04/21, PG 10 OF 27

Evaporator Installation (Cont.)

Figure 5a

Figure 6

1/4-20 x 1” Bolt & Washer

1/4-20 x 1” Bolt & Washer

1/4-20 x 1/2” Button Head

Screw

Firewall

DefrostDoor

Dash/FloorDoor

Bottom Lip of Dash

To Evaporator

To Dash

Front MountingBracket1/4-20

Nut

ECU Module

A/C & HeatBlend Door

4-VentA/C Plenum

NOTE: Once in place, secure the evaporator unit to the firewall.

11

www.vintageair.com

906156 REV I 05/04/21, PG 11 OF 27

Defrost Duct Installation1. Attach the defrost hoses onto the previously removed defrost plenum, and install the plenum onto the

evaporator unit using (2) 10-32 x 1/2" screws (See Photos 1 & 2, below).

Photo 1 Photo 2

Install Defrost Plenum onto Evaporator Unit

Using (2) 10-32 x 1/2" Screws

Attach Defrost Hoses onto Defrost Plenum

Center Vent Installation1. Place the center vent under the dash in the desired position (See Figure 7, below). Drill (2) 1/8” mounting

holes into the bottom lip of the dash, and secure the center vent to the dash using (2) #8 x 1/2” pan head screws (See Figure 7, below).

Figure 7(2) #8 x 1/2”Pan Head Screws

Center Vent

12

www.vintageair.com

906156 REV I 05/04/21, PG 12 OF 27

Figure 8

Figure 9

Under Dash Louver Installation1. Install the driver and passenger side under dash louvers with the flange facing the dash and kick panel

as shown in Figure 8, below. Tuck the kick panel side of the louver flange behind the kick panel windlace retainer, and slide the louver up until the flange is seated against the dash. Secure the louver to the kick panel with (2) #8 x 1/2” pan head screws (See Figure 8, below). NOTE: In most cases, the louvers will fit as described. However, due to dash and kick panel variances, the presence of aftermarket components or modifications, etc., it may be necessary to trim the louver flange and/or slightly move the parking brake lever for proper fit.

Drain Hose Installation1.

2.

In line with the drain, lightly make a mark on the firewall. Measure 1” down and drill a 5/8” hole through the firewall (See Figure 9, below). NOTE: See Figure 14, Page 16, for the rough location of the drain hole.Install the drain hose onto the bottom of the evaporator unit, and route through the firewall (See Figure 9, below, and Figure 14, Page 16).

1” DrainDrain Hose

(2) #8 x 1/2”Pan Head Screws

Flange

NOTE: Install louvers with flange facing the dash and kick panel.

Windlace Retainer

Dash

Windlace Retainer

13

www.vintageair.com

906156 REV I 05/04/21, PG 13 OF 27

Figure 11

Heater Control Valve Installation1. Install the heater control valve in line with the intake manifold (pressure side) heater hose (See Figure 11,

below).

Figure ##

O-ring Installs Over Male Insert to Swaged Lip

O-ring#6 O-ring

#8 O-ring #10 O-ring

O-ring

Supplied Oil for O-rings

Male Insert

Female Nut

Hold With This Wrench

Twist With This Wrench

Lubricating O-rings For a proper seal of fittings: Install supplied O-rings as shown and lubricate with supplied oil.

NOTE: Standard torque specifications:#6: 11 to 13 ft-lb.#8: 15 to 20 ft-lb.

#10: 21 to 27 ft-lb.

Figure 10

ECU Module

#10 SuctionHose

HeaterHoses

#6 Hardline

NOTE: Flow Direction Follows Molded Arrow on Valve.

HoseClamps

From HeaterControl Valve

to Heater Core

From IntakeManifold to

Heater ControlValve

From Heater Coreto Water Pump

14

www.vintageair.com

906156 REV I 05/04/21, PG 14 OF 27

A/C Hardline and Hose Installation

1.2.

3.

4.5.

6.7.

8.

9.

Locate the (2) compressor hardlines (See Figure 12, Page 15).Locate the #8 compressor hardline. Lubricate a #8 O-ring (See Figure 10, Page 13), and connect the #8 compressor hardline to the #8 discharge port on the compressor. Tighten the connection (See Figure 10, Page 13, and Figure 12, Page 15).Locate the #10 compressor hardline. Lubricate a #10 O-ring (See Figure 10, Page 13), and connect the #10 compressor hardline to the #10 suction port on the compressor. Tighten the connection (See Figure 10, Page 13, and Figure 12, Page 15).Secure the (2) compressor hardlines to the compressor using the supplied clamp (See Figure 13, Page 15).Locate the #8 A/C hose. The hose will connect the #8 compressor hardline and the #8 hardline from the condenser. Lubricate (2) #8 O-rings (See Figure 10, Page 13) and install (1) onto each end of the #8 A/C hose. Route the #8 A/C hose as shown in Figure 12, Page 15 and tighten (See Figure 10, Page 13). NOTE: The 90° hose fitting connects to the #8 condenser hardline.Install the firewall cover (See Figure 14, Page 16).Lubricate a #6 O-ring (See Figure 10, Page 13). Install the #6 liquid line and tighten (See Figure 10, Page 13, and Figure 13a, Page 15).Locate the #10 A/C hose. The hose will connect the #10 compressor hardline and the #10 hardline from the evaporator. Lubricate (2) #10 O-rings (See Figure 10, Page 13) and install (1) onto each end of the #10 A/C hose. Route the #10 A/C hose as shown in Figure 12, Page 15, and tighten (See Figure 10, Page 13). NOTE: The 90° hose fitting connects to the #10 compressor hardline.Install the heater hoses onto the heater lines, and route as shown in Figures 12 and 13a, Page 15. Secure with hose clamps. NOTE: This kit does not contain heater hose. The 5/8” heater hose may be purchased from Vintage Air or a local parts retailer.

Standard Hose Kit:

1. Refer to separate instructions included with modified hose kit.Modified Hose Kit:

Liquid Line and Binary Switch Installation1.

2.3.

Install the #6 liquid line onto the drier with a lubricated #6 O-ring (See Figure 10, Page 13) and tighten (See Figure 10, Page 13, and Figure 12, Page 15).Install the binary switch onto the #6 liquid line (See Figure 12, Page 15).Secure the #6 liquid line to the fender using the supplied Adel clamp (See Figure 12, Page 15).

15

www.vintageair.com

906156 REV I 05/04/21, PG 15 OF 27

Figure 12

Figure 13

Figure 13a

A/C and Heater Hose Routing

NOTE: Compressor hardlinesare included with standardhose kit only.

#8 CompressorHardline

35038-VUG-A

#10 CompressorHardline

35037-VUG-A

#8 Condenser Hardline

35018-VCG

#6 Hardline35017-VCGSplit Rubber

Grommet in Core Support Hole

#6 Liquid Line

#10 Suction Hose

HeaterHoses

O-rings

Firewall Cover

#10 Suction Line (Insulated)

Hardline Clamp(Standard Hose Kit Only)

ECU Module

ECU Module

NOTE: Modified hose kits include (2) 135° compressor fittings (Refer to instructions included with modified hose kit).

#6 Hardline

Binary Switch Installation

Binary Switch

#8 Discharge Hose

#6 Liquid Line From Drier to

Expansion Valve09154-PFL

AdelClamp

FirewallCover

ExpansionValve

Press Tape

EvaporatorSub Case

#10 SuctionHose

Heater ControlValve

HeaterHoses

16

www.vintageair.com

906156 REV I 05/04/21, PG 16 OF 27

Figure 14

Firewall Cover Installation1. Pass the lines through the firewall cover, and secure with (2) 7/16” panel retainers (See Figure 14, below).

Passenger SideEvaporator Mounting

Hole1/4-20 x 1”

Bolt & Washer

1/4-20 x 1”Bolt & Washer

(2) 7/16” Panel Retainers

DrainHole

Driver SideEvaporator Bracket

Mounting Hole

FirewallCover

17

www.vintageair.com

906156 REV I 05/04/21, PG 17 OF 27

Wiring Installation1.

2.3.4.5.

Apply (2) strips of Velcro to the ECU, and cut the tie wraps holding the ECU wiring together (See Photos 1 & 2, below). Plug the main wiring harness black connector into the ECU module (See Photo 3, below).Reinstall the control panel into the dash.Plug the control panel connector into the ECU module (See Photo 4, below).Apply (2) strips of Velcro, and mount the ECU to the right of the radio on the inner dash. NOTE: Make sure the area is clean and free of debris before applying the Velcro (See Photo 5, below).

Photo 1 Photo 2

Photo 3 Photo 4

Photo 5

ECU Module

Plug Main Wiring Harness Connectorinto ECU Module

MainWiring Harness Plug Control Panel

Wiring Connector into ECU Module

Inner Dash View

Mount ECU to Right of Radio

Apply (2) Strips of Velcro to

ECU CutTie Wraps

18

www.vintageair.com

906156 REV I 05/04/21, PG 18 OF 27

1. Install the duct hoses as shown in Figure 15, below.

Duct Hose Routing

Figure 15

Passenger SideLouver

2 ½” x 42”

Driver SideLouver

2 ½” x 48”

ECU Module

Driver SideDefrost Duct

2” x 24”

Passenger SideDefrost Duct

2” x 10”

Plug FromWiring Harness232600-VUA

Plug FromControl Panel

Wiring Harness

232002-VUA

Driver SideCenter Vent2 ½” x 15”

Passenger SideCenter Vent2 ½” x 12”

19

www.vintageair.com

906156 REV I 05/04/21, PG 19 OF 27

Glove Box Installation

Final Steps

1.

2.

3.

1.2.

3.4.5.

6.

Install the glove box bottom and glove box door. Secure to the dash with (3) OEM screws (See Figure 16, below).With the glove box bottom and door in place, install the glove box top as shown in Figure 16, below. Using (3) #6 x 3/8” pan head screws, attach the glove box top to the glove box bottom as shown in Figure 16, below.Secure the glove box top to the dash using (2) OEM screws (See Figure 16, below).

Reinstall all previously removed items.Fill radiator with at least a 50/50 mixture of approved antifreeze and distilled water. It is the owner’s responsibility to keep the freeze protection at the proper level for the climate in which the vehicle is operated. Failure to follow antifreeze recommendations will cause heater core to corrode prematurely and possibly burst in A/C mode and/or freezing weather, voiding your warranty.Double check all fittings, brackets and belts for tightness.Vintage Air recommends that all A/C systems be serviced by a licensed automotive A/C technician.Evacuate the system for a minimum of 45 minutes prior to charging, and perform a leak check prior to servicing.Charge the system to the capacities stated on Page 4 of this instruction manual.

Figure 16

Glove BoxDoor

(3) OEMScrews

(2) OEMScrews

PlasticGlove BoxBottom

Glove BoxHinge

Glove BoxTop

(3) #6 x 3/8”Pan HeadScrews

ww

w.v

inta

gea

ir.c

om

20 906156 REV I 05/04/21, PG 20 OF 27

Evap

orat

or H

ard

line

Inst

alla

tion

Fig

ure

17

NO

TE:

Wra

p t

he

#1

0 fi

ttin

g

con

nec

tion

s w

ith

pre

ss t

ape.

#10

O-r

ing

3385

9-VU

F

Pres

s Ta

pe

#10

Suc

tion

Line

0915

1-PC

S

#6

O-r

ing

3385

7-VU

F

Hea

ter

Line

(Eva

pora

tor

to I

ntak

e)09

152-

PCH

Hea

ter

Line

(Eva

pora

tor

to

Wat

er P

ump)

0915

3-PC

H

#6

Har

dlin

e09

150-

PCL

#10

O-r

ing

3385

9-VU

F

1/4-

20 x

1/2

” Bol

t (L

ocat

ed o

n Sub

Cas

e)

Drive

r Sid

eEv

apor

ator

Rear

Bra

cket

6435

4-PC

B

Pass

enge

r Sid

eEv

apor

ator

Re

ar B

rack

et64

355-

PCB

ECU

Mod

ule

1/4-

20 x

1/2

” Bol

t (L

ocat

ed o

n Sub

Cas

e)

21

www.vintageair.com

906156 REV I 05/04/21, PG 21 OF 27

WHT/GRN

WHT/YELWHT/RED

RED

WHTBACKLIGHT NEG

FAN WIPER

MODE WIPER

TEMP WIPER

5V-SW

GND

BACKLIGHT POS

AC ANNUNCIATOR

PRE-WIRED

GEN IV WIRING DIAGRAMREV E, 10/6/2017

GEN IV ECU

PROGRAM

Wiring Diagram

TEMP

MODE

FAN

A/C(IF USED)

232007-VUR

232002-VUA

** CIRCUITBREAKER30 AMP

*** WIDE OPENTHROTTLESWITCH

(OPTIONAL)

* DASH LAMP(IF USED)

Dash lamp is used only with type 232007-VUR harness.Warning: Always mount circuit breaker as close to the battery as possible. (NOTE: Wire betweenbattery and circuit breaker is unprotected and should be carefully routed to avoid a shortcircuit).Wide open throttle switch contacts close only at full throttle, which disables A/C compressor.

JF8

BLK

ORA

TAN

VIEWED FROM WIRE SIDE

* **

***

HEATERCONTROL VALVE

22

www.vintageair.com

906156 REV I 05/04/21, PG 22 OF 27

RED

CIRCUIT BREAKER30 AMP

+

+

-

BLACK

REDWHITE

RED

CHASSIS GROUND

A/CCOMPRESSOR

RELAY

Ignition Switch:

Dash Light:

NOTE: MOUNT RELAYIN DESIRED LOCATION

UNDER DASH

GREEN

FIREWALL

BLUE

BLUE

RED &

WHITE

VIOLET

(IGNITION HOTTERMINAL)

IGNITION SWITCH

DASH BACK LIGHT+0-12vTAN

GRAY

BLUE

WHITE

WHITE

REDRED

WHITE

COMPRESSOR

BATTERY

NOTE: CONNECT WHITEWIRES DIRECTLY TO

(-) BATTERY TERMINAL

BATRUN

12V

RED GREEN

RED

RED

BLUE

LATCH

BLACK

BINARYSAFETYSWITCH

YELLOW

ORANGE

WIRING HARNESS

Violet 12V ignition switch source (key on accessory) position must be switched.

When using a Vintage Air-suppliedcontrol panel, connect the tan wirefrom the Gen IV evaporator wiringharness to the factory dash lights toenable panel backlighting.

Binary: Connect as shown (typical compressor wiring). Be sure compressor body is grounded.

Trinary Switch: Connect according to trinary switch wiring diagram.

Install with servo motor facing down, as shown. Note flow direction arrow molded into valve body and install accordingly.

White must run to (-) battery. Red may run to (+) battery or starter. Mount circuit breaker as close to battery as possible.

Heater Control Valve:

Binary/Trinary & Compressor:

Circuit Breaker/Battery:

CONTROL WIRING HARNESS

NOTE: YELLOW & ORANGE

COMING FROM HARNESS ARE NOT

USED.

WIRING HARNESS

GRAY WIRE IS USED FOR PROGRAMING CONTROLS

IF APPLICABLE

WIRING HARNESS

Gen IV Wiring Connection Instruction

HEATERCONTROL VALVE

WARNING: ALWAYS MOUNT CIRCUIT BREAKER

AS CLOSE TO THE BATTERY AS POSSIBLE. (NOTE: WIRE BETWEEN BATTERY AND CIRCUIT BREAKER IS UNPROTECTED

AND SHOULD BE CAREFULLY ROUTED TO AVOID A SHORT CIRCUIT).

NOTE: HEATER CONTROL VALVE CONNECTION AND CHASSIS GROUND MAY BE LOCATED ON EITHER SIDE OF THE FIREWALL. ENSURECONNECTOR IS LATCHED

FIRMLY.

23

www.vintageair.com

906156 REV I 05/04/21, PG 23 OF 27

Operation of Controls

Adjust to desiredspeed.

Blower SpeedAdjust to desired

speed.

Adjust to desiredmode position (DASH position recommended).

Adjust to desiredspeed.

Adjust to DEFROST position for maximum defrost, or between FLOOR and DEFROST positions for a bi-level

blend (Compressor is automatically engaged).

Adjust to desired temperature.

For A/C operation, adjust tocoldest position to engage

compressor (Adjust between HOT and COLD to reachdesired temperature).

A/C Operation

Heat Operation

Defrost/De-fog Operation

On Gen IV systems with three lever/knob controls, the temperature control toggles between heat and A/C operations. To activate A/C, move the temperature lever/knob all the way to cold and then back it off to the desired vent temperature. For heat operation, move the temperature lever/knob all the way to hot and then adjust to the desired vent temperature. The blower will momentarily change speed, each time you toggle between operations, to indicate the change. NOTE: For proper control panel function, refer to control panel instructions for calibration procedure.

Blower Speed

Blower Speed

This lever/knob controlsblower speed, from

OFF to HI.

This lever/knob controls the mode positions,from DASH to FLOORto DEFROST, with a blend in between.

This lever/knob controlsthe temperature,

from HOT to COLD.

Blower Speed

Mode Control

Temperature Control

Blower Speed

ModeControl

Temperature Control

Temperature Control

Temperature Control

Mode Control

Mode Control

Mode Control

For maximum heating, adjust to hottest position (Adjust between HOT and COLD to reach desired temperature).Adjust to desired

mode position(FLOOR position recommended).

TemperatureControl

DASH FLOOR DEF

OFF FAN HI

HEAT

COLD

DASH FLOOR DEF

OFF FAN HI

HEAT

COLD

DASH FLOOR DEF

OFF FAN HI

HEAT

COLD

DASH FLOOR DEF

OFF FAN HI

HEAT

COLD

ww

w.v

inta

gea

ir.c

om

24 906156 REV I 05/04/21, PG 24 OF 27

Sym

pto

m

Con

dit

ion

Ch

ecks

A

ctio

ns

Not

es

Blo

wer

sta

ys o

n hi

gh s

peed

whe

n ig

nitio

n is

on.

1a.

No

othe

r fu

nctio

ns w

ork.

Che

ck for

dam

aged

pin

s or

w

ires

in c

ontr

ol h

ead

plug

.Ve

rify

tha

t al

l pin

s ar

e in

sert

ed in

to p

lug.

Ens

ure

that

no

pins

are

ben

t or

dam

aged

in E

CU

.Che

ck for

dam

aged

gro

und

wire

(whi

te)

in c

ontr

ol h

ead

harn

ess.

Verify

con

tinui

ty t

o ch

assi

s gr

ound

with

whi

te c

ontr

ol

head

wire

at v

ario

us p

oint

s.

Loss

of gr

ound

on

this

wire

rend

ers

cont

rol h

ead

inop

erab

le.

All

othe

r fu

nctio

ns w

ork.

Che

ck for

dam

aged

blo

wer

sw

itch

or p

oten

tiom

eter

and

as

soci

ated

wirin

g.

Blo

wer

sta

ys o

n hi

gh s

peed

whe

n ig

nitio

n is

on

or o

ff.

Unp

lug

3-w

ire

BSC c

ontr

ol

conn

ecto

r fr

om E

CU

. If

blo

wer

sh

uts

off,

ECU

is e

ither

im

prop

erly

wired

or

dam

aged

.

Be

sure

the

sm

all,

20 G

A w

hite

gro

und

wire

is c

onne

cted

to

the

bat

tery

gro

und

post

. If

it is

, re

plac

e th

e EC

U.

Unp

lug

3-w

ire

BSC c

ontr

ol

conn

ecto

r fr

om E

CU

. If

blo

wer

st

ays

runn

ing,

BSC is

eith

er

impr

oper

ly w

ired

or

dam

aged

.

Che

ck t

o en

sure

tha

t no

BSC w

irin

g is

dam

aged

or

shor

ted

to v

ehic

le g

roun

d. T

he B

SC o

pera

tes

the

blow

er

by g

roun

d si

de p

ulse

wid

th m

odul

atio

n sw

itchi

ng.

The

posi

tive

wire

to t

he b

low

er w

ill a

lway

s be

hot

. If

the

“g

roun

d” s

ide

of t

he b

low

er is

sho

rted

to

chas

sis

grou

nd,

the

blow

er w

ill r

un o

n H

I.

Repl

ace

BSC (

This

will

req

uire

rem

oval

of ev

apor

ator

fr

om v

ehic

le).

No

othe

r pa

rt r

epla

cem

ents

sh

ould

be

nece

ssar

y.

Com

pres

sor

will

no

t tu

rn o

n (A

ll ot

her

func

tions

w

ork)

.

2.

Syst

em is

not

cha

rged

.Sy

stem

mus

t be

cha

rged

for

co

mpr

esso

r to

eng

age.

Cha

rge

syst

em o

r by

pass

pre

ssur

e sw

itch.

Dan

ger

: N

ever

byp

ass

safe

ty s

wit

ch w

ith

en

gin

e ru

nn

ing

. S

erio

us

inju

ry c

an r

esu

lt.

Syst

em is

cha

rged

.

1b

.

Trou

ble

shoo

tin

g G

uid

e

Che

ck for

fau

lty A

/C

pote

ntio

met

er o

r as

soci

ated

w

irin

g (n

ot a

pplic

able

to

3-po

t co

ntro

ls).

Che

ck for

dis

conn

ecte

d or

fa

ulty

the

rmis

tor.

Che

ck c

ontin

uity

to

grou

nd o

n w

hite

con

trol

hea

d w

ire.

Che

ck for

5V o

n re

d co

ntro

l hea

d w

ire.

Che

ck 2

-pin

con

nect

or a

t EC

U h

ousi

ng.

To c

heck

for

pro

per

pot

func

tion,

che

ck v

olta

ge a

t w

hite

/blu

e w

ire.

Vol

tage

sh

ould

be

betw

een

0V a

nd

5V,

and

will

var

y w

ith p

ot

leve

r po

sitio

n.

Dis

conn

ecte

d or

fau

lty

ther

mis

tor

will

cau

se

com

pres

sor

to b

e di

sabl

ed.

Red

wire

at A

/C p

ot s

houl

d ha

ve a

ppro

xim

atel

y 5V

w

ith ig

nitio

n on

. W

hite

w

ire

will

hav

e co

ntin

uity

to

chas

sis

grou

nd.

Whi

te/

Blu

e w

ire

shou

ld v

ary

betw

een

0V a

nd 5

V w

hen

leve

r is

mov

ed u

p or

dow

n.

3. Com

pres

sor

will

no

t tu

rn o

ff

(All

othe

r fu

nctio

ns

wor

k).

Che

ck for

fau

lty A

/C

pote

ntio

met

er o

r as

soci

ated

w

irin

g.

Che

ck for

fau

lty A

/C r

elay

.

Repa

ir o

r re

plac

e po

t/co

ntro

l wirin

g.

Repl

ace

rela

y.

See

blo

wer

sw

itch

chec

k pr

oced

ure.

ww

w.v

inta

gea

ir.c

om

25 906156 REV I 05/04/21, PG 25 OF 27

Sym

pto

m

Con

dit

ion

Ch

ecks

A

ctio

ns

Not

es

Syst

em w

ill n

ot

turn

on,

or

runs

in

term

itten

tly.

4.

Wor

ks w

hen

engi

ne is

not

runn

ing;

shu

ts o

ff w

hen

engi

ne is

sta

rted

(t

ypic

ally

ear

ly G

en I

V,

but

poss

ible

on

all

vers

ions

).

Noi

se in

terf

eren

ce fro

m e

ither

ig

nitio

n or

alte

rnat

or.

Inst

all c

apac

itors

on

igni

tion

coil

and

alte

rnat

or.

Ensu

re

good

gro

und

at a

ll po

ints

. Re

loca

te c

oil a

nd a

ssoc

iate

d w

irin

g aw

ay fro

m E

CU

and

ECU

wirin

g. C

heck

for

bur

ned

or lo

ose

plug

wires

.

Verify

con

nect

ions

on

pow

er

lead

, ig

nitio

n le

ad,

and

both

whi

te g

roun

d w

ires

.

Verify

pro

per

met

er fun

ctio

n by

che

ckin

g th

e co

nditi

on o

f a

know

n go

od b

atte

ry.

Igni

tion

nois

e (r

adia

ted

orco

nduc

ted)

will

cau

se t

he

syst

em t

o sh

ut d

own

due

tohi

gh v

olta

ge s

pike

s. I

f th

isis

sus

pect

ed,

chec

k w

ith a

qu

ality

osc

illos

cope

. Spi

kes

grea

ter

than

16V

will

shu

t do

wn

the

ECU

. In

stal

l a

radi

o ca

paci

tor

at t

he

posi

tive

post

of th

e ig

nitio

nco

il (s

ee r

adio

cap

acito

r in

stal

latio

n bu

lletin

). A

fa

ulty

alte

rnat

or o

r w

orn

out

batt

ery

can

also

res

ult

in t

his

cond

ition

.

Will

not

tur

n on

und

er

any

cond

ition

s.Ve

rify

bat

tery

vol

tage

is

grea

ter

than

10

volts

and

less

than

16.

Loss

of m

ode

door

fu

nctio

n.

No

mod

e ch

ange

at

all.

Che

ck for

dam

aged

mod

e sw

itch

or p

oten

tiom

eter

and

as

soci

ated

wirin

g.

Part

ial f

unct

ion

of m

ode

door

s.

Typi

cally

cau

sed

by

evap

orat

or h

ousi

ng

inst

alle

d in

a b

ind

in t

he

vehi

cle.

Be

sure

all

mou

ntin

g lo

catio

ns li

ne u

p an

d do

n’t

have

to

be for

ced

into

pos

ition

.

Blo

wer

tur

ns o

n an

d of

f ra

pidl

y.

6.

Bat

tery

vol

tage

is a

t le

ast

12V.

Che

ck for

at

leas

t 12

V a

t ci

rcui

t br

eake

r.En

sure

all

syst

em g

roun

ds a

nd p

ower

con

nect

ions

are

cl

ean

and

tight

.

Bat

tery

vol

tage

is le

ss

than

12V

.

5.

Trou

ble

shoo

tin

g G

uid

e (C

ont.

)

Che

ck for

fau

lty b

atte

ry o

r al

tern

ator

.Cha

rge

batt

ery.

Syst

em s

huts

off b

low

er a

t 10

V. P

oor

conn

ectio

ns o

r w

eak

batt

ery

can

caus

e sh

utdo

wn

at u

p to

11V

.

7. Whe

n ig

nitio

n is

tu

rned

on,

blo

wer

m

omen

tarily

co

mes

on,

the

n sh

uts

off.

This

oc

curs

with

the

bl

ower

sw

itch

in

the

OFF

pos

ition

.

This

is a

n in

dica

tor

that

the

sy

stem

has

bee

n re

set.

Be

sure

the

red

pow

er w

ire

is o

nth

e ba

tter

y po

st,

and

not

on a

sw

itche

d so

urce

. Als

o, if

the

sy

stem

is p

ulle

d be

low

7V for

even

a s

plit

seco

nd,

the

syst

em w

ill r

eset

.

Run

red

pow

er w

ire

dire

ctly

to

batt

ery.

Che

ck for

pos

itive

pow

er a

t he

ater

val

ve g

reen

wire

and

blow

er r

ed w

ire.

Che

ck for

gro

und

on c

ontr

ol h

ead

whi

te

wire.

Che

ck for

obs

truc

ted

or

bind

ing

mod

e do

ors.

Che

ck for

dam

aged

ste

pper

m

otor

or

wirin

g.

Erra

tic fun

ctio

ns o

fbl

ower

, m

ode,

te

mp,

etc

.

Che

ck for

dam

aged

sw

itch

or

pot

and

asso

ciat

ed w

irin

g.Re

pair o

r re

plac

e.

8.

ww

w.v

inta

gea

ir.c

om

26 906156 REV I 05/04/21, PG 26 OF 27

NO

TE:

Du

e to

pri

nti

ng

var

ian

ces,

mea

sure

th

e lin

e b

elow

bef

ore

usi

ng

th

is t

emp

late

. If

te

mp

late

is s

cale

d p

rop

erly

, th

e lin

e sh

ould

mea

sure

6 in

ches

.

Cor

e S

up

por

t M

odifi

cati

on T

emp

late

3 9/16”

2 5/16”

1”

5/16”Diameter

3 ¼”

2 ⅜”

2 ⅛”

1/2”

1 ¼”Diameter

Fold

Pag

e at

Thi

s Li

ne a

nd P

ositi

on a

t Ed

ge o

f Cor

e Sup

port

(Re

mov

able

Pan

el)

LocateExisting Holes

27

www.vintageair.com

906156 REV I 05/04/21, PG 27 OF 27

Packing List: Evaporator Kit (56156-PCZ)

No. 1.2.

Qty.11

Part No.76116078256-PCN

DescriptionGen IV Evaporator Sub Case 4-Vent Plenum with 204 ECUAccessory Kit

NOTE: Images may not depict actual parts and quantities. Refer to packing list for actual parts and quantities.

1

2

Gen IV Evaporator Sub Case 4-Vent Plenum

with 204 ECU761160

Accessory Kit78256-PCN

Checked By:Packed By:

Date:

Passenger SideDriver Side