GM Service Manual Online
For 1990-2009 cars only

Tools Required

J 39400-A Halogen Leak Detector

Removal Procedure


    Object Number: 1224339  Size: SH
  1. Remove the HVAC module. Refer to HVAC Module Assembly Replacement .
  2. Remove and discard the HVAC module assembly foam seal.

  3. Object Number: 1226246  Size: SH
  4. Remove the TXV mounting bolts.
  5. Remove the TXV from the evaporator core.
  6. Remove and discard the sealing washers.

  7. Object Number: 1226250  Size: SH
  8. Disconnect the discharge temperature management (DTM) sensor electrical connectors.
  9. Disconnect the HVAC module wiring harness retainer pin (2) from the HVAC module.
  10. Disconnect the wiring harness from the heater core cover wire harness retainer (1) and reposition the wiring harness aside.
  11. Disconnect the wiring harness from the heater core cover wire harness retainer (3) and reposition the wiring harness aside.

  12. Object Number: 1224370  Size: SH
  13. Remove the heater cover screws.
  14. Remove the heater cover from the HVAC module.

  15. Object Number: 1224297  Size: SH
  16. Remove the heater core from the HVAC module.

  17. Object Number: 1224373  Size: SH
  18. Remove the HVAC module case retaining screws.

  19. Object Number: 1224310  Size: SH
  20. Separate the HVAC module upper case from the HVAC module lower case.

  21. Object Number: 1224311  Size: SH
  22. Remove the evaporator core from the HVAC module.

Installation Procedure

  1. If replacing the evaporator core, add the specified amount of PAG oil directly to the evaporator core. Refer to Refrigerant System Capacities .
  2. Important: Line the evaporator core side seal up with the corners of the evaporator core.


    Object Number: 1224314  Size: SH
  3. Install a new side seal to the evaporator core.

  4. Object Number: 1224315  Size: SH
  5. Install a new upper seal to the evaporator core.
  6. Important: Locate the seals at the outer corners of the evaporator core.


    Object Number: 1224316  Size: SH
  7. Install 2 new lower seals to the evaporator core.

  8. Object Number: 1224311  Size: SH
  9. Install the evaporator core to the HVAC module.

  10. Object Number: 1224310  Size: SH
  11. Install the HVAC module upper case to the HVAC module lower case.
  12. 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.


    Object Number: 1224373  Size: SH
  13. Install the HVAC module case retaining screws.
  14. Tighten
    Tighten the screws to 1.6 N·m (14 lb in).


    Object Number: 1224308  Size: SH
  15. Install a new foam seal to the heater core.

  16. Object Number: 1224297  Size: SH
  17. Install the heater core to the HVAC module.
  18. Install the heater cover to the HVAC module.

  19. Object Number: 1224370  Size: SH
  20. Install the heater cover screws.
  21. Tighten
    Tighten the screws to 1.6 N·m (14 lb in).


    Object Number: 1226250  Size: SH
  22. Reposition the HVAC wiring harness and connect the wiring harness to the heater core cover wiring harness retainer (1).
  23. Reposition the HVAC wiring harness and connect the wiring harness to the heater core cover wiring harness retainer (3).
  24. Connect the HVAC module wiring harness retainer pin (2) to the HVAC module.
  25. Connect the discharge temperature management (DTM) sensor electrical connectors.

  26. Object Number: 1226246  Size: SH
  27. Install new sealing washers to the evaporator core. Refer to Sealing Washer Replacement .
  28. Install the TXV to the evaporator core.
  29. Install the TXV to mounting bolts.
  30. Tighten
    Tighten the bolts to 7 N·m (62 lb in).

  31. Install the HVAC module. Refer to HVAC Module Assembly Replacement .