Housing Assembly HVAC: Service and Repair

AIR CONDITIONING AND HEATER MODULE ASSEMBLY REPLACEMENT

TOOLS REQUIRED
J 39400-A Halogen Leak Detector

REMOVAL PROCEDURE

CAUTION: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

For Vehicles equipped with OnStar (UE1) with Back Up Battery:

The Back Up Battery is a redundant power supply to allow limited OnStar� functionality in the event of a main vehicle battery power disruption to the VCIM (OnStar�module). Do not disconnect the main vehicle battery or remove the OnStar� fuse with the ignition key in any position other than OFF. Retained accessory power (RAP) should be allowed to time out or be disabled (simply opening the driver door should disable RAP) before disconnecting power. Disconnecting power to the OnStar� module in any way while the ignition is On or with RAP activated may cause activation of the OnStar� Back-Up Battery (BUB) system and will discharge and permanently damage the back-up battery. Once the Back-Up Battery is activated it will stay on until it has completely discharged. The BUB is not rechargeable and once activated the BUB must be replaced.


CAUTION: Refer to Battery Disconnect Caution in Service Precautions.





1. Disconnect the negative battery cable.
2. Recover the refrigerant. Refrigerant Recovery and Recharging
3. Drain the engine coolant.
4. Raise the vehicle.
5. Remove the evaporator hose from the evaporator.
6. Lower the vehicle.
7. Remove the inlet heater hose from the heater core.
8. Remove the outlet heater hose from the heater core.
9. Raise the vehicle.
10. Remove the drain tube elbow from the evaporator block heater case plate.





11. Remove the nuts holding the heater case plate for the heater pipes.
12. Remove the heater case plate and the seals for the heater pipes.
13. Remove the nuts holding the heater case plate for the evaporator block.
14. Remove the heater case plate and seal for the evaporator block.
15. Remove the nut for the HVAC module assembly bracket.
16. Lower the vehicle.
17. Remove the air cleaner assembly from the vehicle.
18. Release the under hood electrical center and position aside.





19. Loosen the steering column brace bolts (1) behind the under hood electrical center.





20. Remove the instrument panel carrier. Instrument Panel (IP) - Carrier Replacement
21. Remove the bolt from the bracket joining the cross vehicle beam to the HVAC module.





22. Release the body control module from the cross vehicle beam.
23. Remove HVAC duct work from the cross vehicle beam.





24. Remove the 2 remaining bolts for the steering column brace.





25. Remove the nuts and bolts joining the cross vehicle beam (1) to the front of the dash (2).





26. Remove the cross vehicle beam from the vehicle.
27. Remove the floor air duct from the HVAC module.
28. Remove the air distribution duct.





29. Remove the daytime running lights sensor wiring harness clip (1) from the HVAC module assembly.
30. Disconnect the IP lamp dimmer switch electrical connector (2).
31. Remove the wiring harness clips (3) from the HVAC module assembly bracket.
32. Disconnect the vacuum source hose (4) from the vacuum tank.





33. Disconnect the blower motor resistor electrical connector.
34. Disconnect the blower motor electrical connector.





35. Disconnect the temperature actuator electrical connector.





36. Remove the HVAC module assembly.

INSTALLATION PROCEDURE





1. Position the HVAC module assembly to the vehicle.





2. Connect the temperature actuator electrical connector.





3. Connect the blower motor resistor electrical connector.
4. Connect the blower motor electrical connector.





5. Install the wiring harness clips (3) to the HVAC module assembly bracket.
6. Install the daytime running lights sensor wiring harness clip (1) from the HVAC module assembly.
7. Connect the IP lamp dimmer switch electrical connector (2).
8. Connect the vacuum supply hose (4) to the vacuum tank.
9. Install the air distribution duct.
10. Install the floor air duct to the HVAC module.





11. Install the cross vehicle beam (1) to the front of the dash (2).

NOTE: Refer to Fastener Notice in Service Precautions.

12. Install the nuts and bolts for the cross vehicle beam.

Tighten
Tighten the nut and bolts to 20 Nm (15 lb ft).





13. Install the steering column mounting brace bolts.

Tighten
Tighten the bolts to 26 Nm (19 lb ft).





14. Install HVAC duct work to the cross vehicle beam.
15. Install the body control module to the cross vehicle beam.





16. Connect the wiring harness to the cross vehicle beam.





17. Install the bolt retaining the cross vehicle beam to the HVAC module.

Tighten
Tighten the bolt retaining the cross vehicle beam to the HVAC module to 10 N.m (89 lb in).

18. Install the instrument panel carrier to the cross vehicle beam.





19. Tighten the steering column brace bolts (1) behind the under hood electrical center for the steering column brace.

Tighten
Tighten the bolts to 26 Nm (19 lb ft).

20. Install the under hood electrical center.
21. Install the air cleaner assembly to the vehicle.





22. Raise the vehicle.
23. Install the nut for the HVAC module assembly bracket.

Tighten
Tighten the bracket nut to 10 Nm (89 lb in).

24. Install the heater case plate and the seals for the heater pipes.
25. Install the nuts holding the heater case plate for the heater pipes.
26. Install the heater case plate and seal for the evaporator block.
27. Install the nuts holding the heater case plate for the evaporator block.

Tighten
Tighten the heater case plates nuts to 10 Nm (89 lb in).





28. Install the drain tube elbow to the evaporator block heater case plate.
29. Install the evaporator hose to the evaporator.
30. Install the outlet heater hoses to the heater core.
31. Install the inlet heater hose to the heater core.
32. Lower the vehicle.
33. Connect the negative battery cable.
34. Fill the engine cooling system.
35. Recharge the A/C system.
36. Leak test the fittings of the component using the J 39400-A.