GM Service Manual Online
For 1990-2009 cars only

Removal Procedure


    Object Number: 1224374  Size: SH
  1. Remove the HVAC module. Refer to HVAC Module Assembly Replacement.
  2. Disconnect the LH air temperature actuator electrical connector.
  3. Remove the LH actuator retaining screws.
  4. Remove the LH actuator.

  5. Object Number: 1224325  Size: SH
  6. Disconnect the mode actuator electrical connector.
  7. Disconnect the RH air temperature actuator electrical connector.
  8. Remove the actuator support bracket retaining screws.
  9. Remove the actuator support bracket and actuators.
  10. Caution: Do not remove the TORX screws from the mode valve assembly. Misalignment can cause damage to the film valve.


    Object Number: 1224372  Size: SH
  11. Remove the mode valve assembly retaining screws.

  12. Object Number: 1226250  Size: SH
  13. Disconnect the HVAC module wiring harness retainer pin (1) from the HVAC module.
  14. Disconnect the wiring harness from the heater core cover wire harness retainer (2) and reposition the wiring harness aside.
  15. Disconnect the discharge temperature management (DTM) sensor electrical connectors.

  16. Object Number: 1224370  Size: SH
  17. Remove the heater core cover screws.
  18. Remove the heater core cover.

  19. Object Number: 1224371  Size: SH
  20. Remove the mode valve assembly.

Installation Procedure

    Caution: Do not tamper, adjust or disassemble the mode valve assembly. The proper setting of the pretensions on the springs is critical to the film valve function.


    Object Number: 1224371  Size: SH
  1. Install the mode valve assembly.
  2. Install the heater core cover.
  3. Caution: Refer to Fastener Caution in the Preface section.


    Object Number: 1224370  Size: SH
  4. Install the heater core cover screws and tighten to 1.6 N·m (14 lb in).
  5. Connect the wiring harness to the heater core cover wire harness retainer (2).

  6. Object Number: 1226250  Size: SH
  7. Connect the HVAC module wiring harness retainer pin (1) to the HVAC module.
  8. Connect the discharge temperature management (DTM) sensor electrical connectors.

  9. Object Number: 1224372  Size: SH
  10. Install the mode valve assembly retaining screws and tighten to 1.6 N·m (14 lb in).

  11. Object Number: 1224325  Size: SH

    Note: It may be necessary to gently rotate the RH temperature door to align the actuator support bracket and actuators.

  12. Install the actuator support bracket and actuators to the HVAC module.
  13. Install the actuator support bracket retaining screws and tighten to 1.6 N·m (14 lb in).
  14. Connect the RH air temperature actuator electrical connector.
  15. Connect the mode actuator electrical connector.
  16. Install the LH actuator.
  17. Install the LH actuator retaining screws.
  18. Connect the LH air temperature actuator electrical connector.

  19. Object Number: 1224374  Size: SH
  20. Install the HVAC module. Refer to HVAC Module Assembly Replacement.