GM Service Manual Online
For 1990-2009 cars only

Removal Procedure

  1. Remove the HVAC module from the vehicle. Refer to HVAC Module Assembly Replacement.

  2. Object Number: 1548653  Size: SH
  3. Remove the heat stakes from the heater core cover using a small chisel and remove the cover.

  4. Object Number: 872606  Size: SH
  5. Remove the heater core.

  6. Object Number: 1548656  Size: SH
  7. Remove the heat stakes that secure the lower HVAC case to the HVAC module using a small chisel.

  8. Object Number: 877662  Size: SH
  9. Unsnap and open the passenger compartment filter door.
  10. Remove the lower HVAC case.

  11. Object Number: 877663  Size: SH
  12. Remove the evaporator core.

Installation Procedure


    Object Number: 877663  Size: SH
  1. Install the evaporator core into the HVAC module assembly.

  2. Object Number: 877662  Size: SH

    Note: Verify that the orifice plate is correctly positioned in the HVAC module. Verify that the lower HVAC case is properly positioned and is fully seated on the HVAC module. Install new screws that will secure the lower HVAC case to the HVAC module.

  3. Install the lower HVAC case.
  4. Caution: Refer to Fastener Caution in the Preface section.


    Object Number: 877661  Size: SH
  5. Install the lower HVAC case screws.
  6. Tighten
    Tighten the screws to 1.8 N·m (16 lb in).

  7. Close and secure the passenger compartment filter door.

  8. Object Number: 872606  Size: SH
  9. Inspect the foam heater core seal on the lower HVAC case. If damaged, replace using Kent Industries adhesive black foam tape P/N 46480 or equivalent.
  10. Install the heater core into the HVAC module.

  11. Object Number: 877660  Size: SH

    Note: Verify that the heater core cover is properly positioned and is fully seated on the HVAC module. Install new screws that secure the heater core cover to the HVAC module.

  12. Install the heater core cover and the screws.
  13. Tighten
    Tighten the screws to 1.8 N·m (16 lb in).


    Object Number: 872602  Size: SH
  14. Replace the drain tube seal.

  15. Object Number: 873734  Size: SH
  16. Replace the front of dash seal.
  17. Inspect and replace the following HVAC module seals if damaged:
  18. • The defrost duct seal
    • The HVAC module to cross car duct seal
    • The center air outlet duct seal
    • The center floor air outlet duct seal
    • The air inlet seal
  19. Install the HVAC module in the vehicle. Refer to HVAC Module Assembly Replacement.
  20. Evacuate and charge the refrigerant system. Refer to Refrigerant Recovery and Recharging.
  21. Leak test the fittings using J 39400-A .
  22. Fill the cooling system. Refer to Cooling System Draining and Filling.