GM Service Manual Online
For 1990-2009 cars only

Removal Procedure

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


    Object Number: 1256099  Size: SH
  1. Disconnect the negative battery cable.
  2. Remove the instrument panel (IP) assembly. Refer to Instrument Panel Assembly Replacement in Instrument Panel, Gages, and Console.
  3. Drain the cooling system. Refer to Cooling System Draining and Filling in Engine Cooling.
  4. If equipped with A/C recover the refrigerant. Refer to Refrigerant Recovery and Recharging .
  5. If equipped with A/C remove the retaining nuts that secure the suction hose and the liquid evaporator pipe blocks at the cowl.

  6. Object Number: 1255879  Size: SH
  7. If equipped with A/C loosen the clamp bolts from the suction hose and the liquid evaporator pipe to allow movement of the hose and the pipe.
  8. If equipped with A/C remove the evaporator drain hose.
  9. Compress the heater hose clamps at the cowl and slide the clamps toward the engine.
  10. Remove the 2 heater hoses from the core lines at the cowl.
  11. If equipped with A/C remove the screws that secure the HVAC module to the cowl on either side of the heater hoses.

  12. Object Number: 1255880  Size: SH
  13. Remove the HVAC module screw, that is located above the fuel filter, from the engine compartment side of the cowl.
  14. Have an assistant support the HVAC module from inside the vehicle.

  15. Object Number: 1255881  Size: SH
  16. Remove the HVAC module screws from the evaporator flange on the engine compartment side of the cowl. The HVAC module will start to drop.
  17. Pull the case straight away from the cowl.
  18. Remove the HVAC module from the vehicle.

Installation Procedure


    Object Number: 1255881  Size: SH
  1. Position the HVAC module in the vehicle.
  2. Important: To avoid damaging the heater core tubes, make sure they do not contact the cowl opening.

  3. Slowly raise the HVAC module into position and hold it against the cowl while the screws are installed and tightened from the engine side of the cowl.
  4. Notice: Refer to Fastener Notice in the Preface section.

  5. Align and install the HVAC module screws above the fuel filter and at the evaporator flange.
  6. Tighten
    Tighten the HVAC module screws to 8 N·m (71 lb in).


    Object Number: 1256104  Size: SH
  7. Install the HVAC module screws adjacent to the heater hoses.
  8. Tighten
    Tighten the HVAC module screws to 8 N·m (71 lb in).

  9. Install the evaporator drain hose.

  10. Object Number: 1255879  Size: SH
  11. Install the 2 heater hoses.
  12. Slide the heater hose clamps into position.
  13. Install the instrument panel (IP) assembly. Refer to Instrument Panel Assembly Replacement in Instrument Panel, Gages, and Console.

  14. Object Number: 1256099  Size: SH
  15. Install new O-rings on the suction hose and the liquid evaporator pipe at the cowl and put the pipes back in place.
  16. Install the retaining nuts that secure the suction hose and the liquid evaporator pipe blocks at the cowl.
  17. Tighten
    Tighten the suction hose and the liquid evaporator pipe retaining nuts to 10 N·m (89 lb in).

  18. Fill the cooling system. Refer to Cooling System Draining and Filling in Engine Cooling.
  19. Recharge the A/C system. Refer to Refrigerant Recovery and Recharging .
  20. Connect the negative battery cable.