GM Service Manual Online
For 1990-2009 cars only

Tools Required

J 39400-A Halogen Leak Detector

Removal Procedure

  1. Recover the refrigerant from the A/C system. Refer to Refrigerant Recovery and Recharging .
  2. Drain the cooling system. Refer to Cooling System Draining and Filling.
  3. Remove the heater pipe assembly . Refer to Heater Pipes Replacement .

  4. Object Number: 945438  Size: SH
  5. Remove the evaporator drain tube (1) from the HVAC module.
  6. Remove the instrument panel (I/P) assembly. Refer to Instrument Panel Assembly Replacement.
  7. Remove the air distribution duct. Refer to Air Distributor Duct Replacement .

  8. Object Number: 943433  Size: SH
  9. Remove the retainers from the upper defogger duct on the left side window.
  10. Disconnect and remove the upper defogger outlet duct.

  11. Object Number: 1224615  Size: SH
  12. Disconnect the head-up display (HUD) electrical connector.
  13. Remove the HUD retaining nuts.
  14. Remove the screw that secures the HUD to the steering column bracket.

  15. Object Number: 943424  Size: SH
  16. Remove the retainer from the lower defogger outlet duct.
  17. Disconnect and remove the outlet duct from the defroster duct.

  18. Object Number: 943584  Size: SH
  19. Remove the retaining screws from the floor air outlet duct.
  20. Remove the outlet duct.

  21. Object Number: 943438  Size: SH
  22. Remove the retainers from the upper outlet duct on the right side window defogger.
  23. Disconnect and remove the defogger upper outlet duct from the defogger lower outlet duct.

  24. Object Number: 943428  Size: SH
  25. Disconnect the defogger lower outlet duct from the knee bolster bracket.
  26. Disconnect the defogger lower outlet duct from the defroster duct.
  27. Remove the defogger lower outlet duct.
  28. Remove the SIR bracket. Refer to Instrument Panel Inflatable Restraint Module Bracket Replacement .

  29. Object Number: 943568  Size: SH
  30. Remove the retaining screws from the floor air outlet duct.
  31. Remove the air outlet duct.

  32. Object Number: 1229604  Size: SH
  33. Remove the defroster duct retaining screws.
  34. Remove the defroster duct.
  35. Disconnect the blower motor electrical connector.

  36. Object Number: 907907  Size: SH
  37. Remove the blower motor retaining screws.
  38. Remove the blower motor from the HVAC module.

  39. Object Number: 1230181  Size: SH
  40. Remove the retaining and sealing nuts from the cowl.
  41. Remove the retaining bolts from the upper I/P cross vehicle beam.
  42. Completely loosen the studs on the HVAC module.

  43. Object Number: 1247571  Size: SH

    Important: Reposition the HVAC module rearward to access the front left-hand (LH) screw.

    The front LH retaining tab of the recirculation housing is slotted.

  44. Loosen the front LH recirculation housing retaining screw.

  45. Object Number: 1226128  Size: SH
  46. Disconnect the recirculation actuator electrical connector.
  47. Disconnect the HVAC module wiring harness from the recirculation housing.

  48. Object Number: 1247576  Size: SH
  49. Remove the remaining recirculation housing retaining screws.
  50. Remove the recirculation housing from the HVAC module.
  51. Important: Reposition the center console wiring harness that runs beneath the HVAC module to aide in HVAC module removal.

  52. Reposition the center console wiring harness and the corresponding electrical connectors to the sides of the HVAC module and forward of the lower tie bar.

  53. Object Number: 1247574  Size: SH
  54. Carefully remove the HVAC module from the vehicle.

  55. Object Number: 1229638  Size: SH
  56. Remove and discard the air inlet, drain and plumbing seals from the HVAC module.

Installation Procedure

  1. If a new HVAC module is being installed, add the specified amount of PAG oil to the evaporator core. Refer to Refrigerant System Capacities .
  2. Notice: Refer to Fastener Notice in the Preface section.

  3. Install the HVAC module studs.
  4. Tighten
    Tighten the studs to 4 N·m (35 lb in).


    Object Number: 1229638  Size: SH
  5. Install new air inlet, drain and plumbing seals to the HVAC module.
  6. Important: Ensure that the cut-outs on the dash-mat are properly aligned so that the drain and plumbing seals are seated directly against the cowl and the air inlet seal is seated directly against the dash-mat.

    The opening in the dash-mat for the HVAC module drain should be aligned so that the drain opening in the cowl is approximately centered in the dash-mat opening; allowing ample room for the module drain seal to fully seat against the cowl.

  7. Inspect the dash-mat for proper alignment to the cowl. Align if necessary.

  8. Object Number: 1247574  Size: SH

    Notice: Do not force the HVAC module between upper I/P and lower I/P cross vehicle beams. Damage to the HVAC module can result.

    Important: Spray a light coat of 3M™ P/N 08877 Silicone Lubricant Plus or equivalent onto the HVAC module heater cover to aid in the installation process.

  9. Install the HVAC module into the vehicle.
  10. Reposition the center console wire harness and the corresponding electrical connectors rearward of the lower tie bar.
  11. Install the recirculation housing to the HVAC module.

  12. Object Number: 1247576  Size: SH
  13. Install the recirculation housing retaining screws.
  14. Tighten
    Tighten the screws to 1.6 N·m (14 lb in).

  15. Connect the HVAC module wiring harness to the recirculation housing.

  16. Object Number: 1226128  Size: SH
  17. Connect the recirculation actuator electrical connector.

  18. Object Number: 1247571  Size: SH
  19. Tighten the front LH recirculation housing retaining screw.
  20. Tighten
    Tighten the screw to 1.6 N·m (14 lb in).

    Important: If necessary, gently rotate the HVAC module forward to engage the HVAC module studs through the corresponding holes on the cowl.


    Object Number: 1229659  Size: SH
  21. Align the following components to the corresponding openings on the cowl:
  22. • The heater core block fitting
    • The evaporator block fitting
    • The HVAC module drain
    • The HVAC module studs

    Object Number: 1230181  Size: SH
  23. Install the bolts retaining the HVAC module to the upper I/P cross vehicle beam.
  24. Tighten
    Tighten the bolts to 5 N·m (44 lb in).

    Important: To prevent possible water leaks or wind/road noise from entering the vehicle passenger compartment, do not reuse the old HVAC module retaining and sealing nuts.

  25. Install new HVAC module retaining and sealing nuts.
  26. Tighten
    Tighten the nuts to 10 N·m (89 lb in).


    Object Number: 907907  Size: SH
  27. Install the blower motor to the HVAC module.
  28. Install the blower motor retaining screws.
  29. Tighten
    Tighten the screws to 1.6 N·m (14 lb in).

  30. Connect the blower motor electrical connector.

  31. Object Number: 1229604  Size: SH
  32. Install the defroster duct to the HVAC module.
  33. Install the defroster duct retaining screws.
  34. Tighten
    Tighten the screws to 10 N·m (89 lb in).

  35. Install the right floor air outlet duct.

  36. Object Number: 943568  Size: SH
  37. Install the floor air outlet duct retaining screws.
  38. Tighten
    Tighten the screws to 1.6 N·m (14 lb in).

  39. Install the lower outlet duct to the side window defogger.
  40. Connect the lower outlet duct on the side window defogger to the defroster duct.
  41. Remove the SIR bracket. Refer to Instrument Panel Inflatable Restraint Module Bracket Replacement .

  42. Object Number: 943428  Size: SH
  43. Connect the defogger lower outlet duct to the knee bolster bracket.
  44. Connect the defogger upper outlet duct to the defogger lower outlet duct.

  45. Object Number: 943438  Size: SH
  46. Install the retainers to the defogger upper outlet duct.
  47. Install the left rear floor air outlet duct.

  48. Object Number: 943584  Size: SH
  49. Install the floor air outlet duct retaining screws.
  50. Tighten
    Tighten the screws to 1.6 N·m (14 lb in).

  51. Connect the window defogger lower outlet duct to the defroster duct.

  52. Object Number: 943424  Size: SH
  53. Install the defogger lower outlet duct retainer.
  54. Install the screw that secures the HUD to the steering column bracket.
  55. Tighten
    Tighten the screw to 3 N·m (27 lb in).

  56. Install the HUD retaining nuts.
  57. Tighten
    Tighten the nuts to 5 N·m (44 lb in).


    Object Number: 1224615  Size: SH
  58. Connect the HUD electrical connector.
  59. Connect the defogger upper outlet duct.

  60. Object Number: 943433  Size: SH
  61. Install the retainers to the upper defogger duct.
  62. Install the air distribution duct. Refer to Air Distributor Duct Replacement .
  63. Install the I/P assembly. Refer to Instrument Panel Assembly Replacement .

  64. Object Number: 945438  Size: SH

    Important: Ensure that the evaporator drain tube is fully seated to the HVAC module.

  65. Install the evaporator drain tube  (1) to the HVAC module.
  66. Install the heater pipe assembly . Refer to Heater Pipes Replacement .
  67. Fill the cooling system. Refer to Cooling System Draining and Filling .
  68. Evacuate and recharge the A/C system. Refer to Refrigerant Recovery and Recharging .
  69. Leak test the fittings of the component using J 39400-A .