GM Service Manual Online
For 1990-2009 cars only

Tools Required

J 39400-A Halogen Leak Detector

Removal Procedure

  1. Recover the refrigerant. Refer to Refrigerant Recovery and Recharging .
  2. Remove the left fender diagonal brace. Refer to Front Fender Upper Diagonal Brace Replacement in Body Front End.
  3. Remove the cross vehicle brace. Refer to Cross Vehicle Brace Replacement in Body Front End.
  4. Drain the cooling system. Refer to Cooling System Draining and Filling in Engine Cooling.
  5. Disconnect the A/C lines at the evaporator block fitting. Refer to Evaporator Tube Replacement .
  6. Disconnect the heater hoses at the heater core. Refer to Heater Hoses Replacement .
  7. Remove the cross vehicle beam. Refer to Instrument Panel Tie Bar Replacement in Instrument Panel, Gauges and Console.
  8. Disconnect the vacuum hoses from the HVAC control module.
  9. Disconnect the electrical connectors from the HVAC control module.
  10. Disconnect the IP wiring harness from the HVAC control module retainers and position the IP wiring harness to the floor.

  11. Object Number: 282300  Size: SH
  12. Remove the evaporator drain elbow.

  13. Object Number: 507700  Size: SH
  14. Remove the HVAC control module to dash nuts.
  15. Preform the following steps to remove the HVAC control module.
  16. 13.1. Pull the HVAC control module rearward to disengage the mounting studs from the dash panel.
    13.2. Position aside the dash insulator pad from the HVAC control module recirculation opening.
    13.3. Roll the HVAC control module downward and rearward to disconnect the heater core outlet cover from the rear floor air outlet duct.
    13.4. Remove the HVAC control module.

    Object Number: 283719  Size: SH
  17. Remove and discard all of the outer HVAC control module seals (1, 2 ,3).

Installation Procedure


    Object Number: 283719  Size: SH
  1. Install new outer HVAC control module seals (1 ,2, 3).
  2. Important:  When installing the HVAC control module, ensure dash insulator pad cut-outs and HVAC seals, studs, and drain align and seal properly to dash panel.

  3. Preform the following steps to install the HVAC control module into the vehicle.
  4. 2.1. Align the HVAC control module heater core outlet cover to the rear floor air outlet duct.
    2.2.  Roll the HVAC control module forward and upward and align the dash insulator pad to the HVAC control module recirculation opening.
    2.3. Align the HVAC control module mounting studs and drain to seat against the dash panel.

    Object Number: 507700  Size: SH

    Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  5. Install the HVAC control module to dash nuts.
  6. Tighten
    Tighten the HVAC control module nuts to 10 N·m (89 lb in).


    Object Number: 282300  Size: SH
  7. Install the evaporator drain elbow.
  8. Position the IP wiring harness to the HVAC control module and secure in the harness retainers.
  9. Connect the electrical connectors to the HVAC control module.
  10. Connect the vacuum hoses to the HVAC control module.
  11. Install the cross vehicle beam. Refer to Instrument Panel Tie Bar Replacement in Instrument Panel, Gauges and Console.
  12. Connect the heater hoses at the heater core. Refer to Heater Hoses Replacement in Engine Cooling.
  13. Install the A/C lines at the evaporator block fitting. Refer to Evaporator Tube Replacement .
  14. Fill the cooling system. Refer to Cooling System Draining and Filling in Engine Cooling.
  15. Install the cross vehicle brace. Refer to Cross Vehicle Brace Replacement in Body Front End.
  16. Install the left fender diagonal brace. Refer to Front Fender Upper Diagonal Brace Replacement in Body Front End.
  17. Evacuate and recharge the A/C system. Refer to Refrigerant Recovery and Recharging .
  18. Leak test the fittings of the component using J 39400-A .