GM Service Manual Online
For 1990-2009 cars only

HVAC Module Assembly Replacement Gasoline Engine

Removal Procedure

    Caution: Refer to Battery Disconnect Caution in the Preface section.


    Object Number: 1308255  Size: SH
  1. Disconnect the negative battery.
  2. Remove the instrument panel and tie-bar. Refer to Instrument Panel Assembly Replacement .
  3. Drain the cooling system. Refer to Cooling System Draining and Filling .
  4. Compress the heater hose clamps at the cowl and slide the clamps toward the engine.
  5. Remove the 2 heater hoses from the core pipes and the cowl.

  6. Object Number: 1308256  Size: SH
  7. Remove the screws that secure the heater/air distributor case assembly to the cowl on the side of the heater core pipes.

  8. Object Number: 1308264  Size: SH
  9. Remove the high-pressure and low-pressure pipe from the A/C expansion valve.

  10. Object Number: 1308283  Size: SH
  11. Remove the evaporator drain hose.
  12. Have an assistant support the heater/air distributor case from inside the vehicle.
  13. Remove the screws that secure the heater/air distributor case assembly to the cowl on the side of the evaporator.
  14. Disconnect the rear duct connector.
  15. Notice: Use care when handling the heater case to avoid damaging the mode linkage levers.

  16. Remove the heater/air distributor case assembly from the vehicle.

Installation Procedure


    Object Number: 1308287  Size: SH
  1. Position the heat/air distributor case assembly in the vehicle.
  2. Important: Avoid damaging the heater core pipes by making sure they do not contact the cowl opening.

  3. Slowly raise the heater/air distributor case assembly into position against the cowl and hold it in position while the screws are installed and tighten from the engine side of the cowl.
  4. Install the high pressure and low pressure pipe.
  5. Notice: Refer to Fastener Notice in the Preface section.

  6. Install the heater/air distributor case assembly screws at the side of evaporator through the cowl from the engine compartment side.
  7. Tighten
    Tighten the heater/air distributor case assembly screws to 4 N·m (35 lb in).


    Object Number: 1308288  Size: SH
  8. Install the heater/air distributor case assembly screws at the side of the heater core pipes through the cowl from the engine compartment side.
  9. Tighten
    Tighten the heater/air distributor case assembly screws to 4 N·m (35 lb in).

  10. Install the 2 heater hoses.
  11. Slide the heater hose clamps into position.
  12. Connect the rear duct connector.
  13. Install the instrument panel and tie-bar. Refer to Instrument Panel Assembly Replacement .
  14. Fill the cooling system. Refer to Cooling System Draining and Filling .
  15. Connect the negative battery cable.
  16. Operate the controls to verify the proper function of the heating and ventilation systems.

HVAC Module Assembly Replacement Diesel Engine

Removal Procedure

    Caution: Refer to Battery Disconnect Caution in the Preface section.


    Object Number: 1887931  Size: SH
  1. Disconnect the negative battery.
  2. Remove the instrument panel and tie-bar. Refer to Instrument Panel Assembly Replacement .
  3. Drain the cooling system. Refer to Cooling System Draining and Filling .
  4. Compress the heater hose clamps at the cowl and slide the clamps toward the engine.
  5. Remove the 2 heater hoses from the core pipes and the cowl.

  6. Object Number: 1308256  Size: SH
  7. Remove the screws that secure the heater/air distributor case assembly to the cowl on the side of the heater core pipes.

  8. Object Number: 1308264  Size: SH
  9. Remove the high-pressure and low-pressure pipe from the A/C expansion valve.

  10. Object Number: 1308283  Size: SH
  11. Remove the evaporator drain hose.
  12. Have an assistant support the heater/air distributor case from inside the vehicle.
  13. Remove the screws that secure the heater/air distributor case assembly to the cowl on the side of the evaporator.
  14. Disconnect the rear duct connector.
  15. Notice: Use care when handling the heater case to avoid damaging the mode linkage levers.

  16. Remove the heater/air distributor case assembly from the vehicle.

Installation Procedure


    Object Number: 1308287  Size: SH
  1. Position the heat/air distributor case assembly in the vehicle.
  2. Important: Avoid damaging the heater core pipes by making sure they do not contact the cowl opening.

  3. Slowly raise the heater/air distributor case assembly into position against the cowl and hold it in position while the screws are installed and tighten from the engine side of the cowl.
  4. Install the high pressure and low pressure pipe.
  5. Notice: Refer to Fastener Notice in the Preface section.

  6. Install the heater/air distributor case assembly screws at the side of evaporator through the cowl from the engine compartment side.
  7. Tighten
    Tighten the heater/air distributor case assembly screws to 4 N·m (35 lb in).


    Object Number: 1308288  Size: SH
  8. Install the heater/air distributor case assembly screws at the side of the heater core pipes through the cowl from the engine compartment side.
  9. Tighten
    Tighten the heater/air distributor case assembly screws to 4 N·m (35 lb in).

  10. Install the 2 heater hoses.
  11. Slide the heater hose clamps into position.
  12. Connect the rear duct connector.
  13. Install the instrument panel and tie-bar. Refer to Instrument Panel Assembly Replacement .
  14. Fill the cooling system. Refer to Cooling System Draining and Filling .
  15. Connect the negative battery cable.
  16. Operate the controls to verify the proper function of the heating and ventilation systems.