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HOMESERVICE MANUALSCHEVROLET2003TRAILBLAZER 4.2 S, 4WDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 1229 (HEATING, VENTILATION AND AIR CONDITIONING)REPAIR INSTRUCTIONSHVAC MODULE ASSEMBLY REPLACEMENTREMOVAL PROCEDURE
2003 Chevrolet TrailBlazer 4.2 S, 4WD

Removal Procedure

2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Removal Procedure
WARNING: This page is about a different car, the 2003 Pontiac Grand Prix. However, it is still accessible from the selected car via links, so may be relevant.
  1. Recover the refrigerant. Refer to Refrigerant Recovery And Recharging  .
  2. Disconnect the battery negative cable. Refer to BATTERY NEGATIVE CABLE DISCONNECT/CONNECT PROCEDURE .
  3. Remove the air cleaner assembly.
  4. Remove the fuel injector sight shield (3.8L only). Refer to FUEL INJECTOR SIGHT SHIELD REPLACEMENT (L36) or FUEL INJECTOR SIGHT SHIELD REPLACEMENT (L67) .
  5. Drain the cooling system. Refer to DRAINING AND FILLING COOLING SYSTEM .
  6. Remove the I/P trim pad. Refer to TRIM PAD REPLACEMENT - INSTRUMENT PANEL (I/P) .
  7. Remove the passenger side SIR inflator module. Refer to REMOVAL & INSTALLATION (PASSENGER-SIDE) .
  8. Remove the screws from the right and left side air distribution duct.
  9. Remove the right and left side air distribution duct.
    Fig 1: Removing Right & Left Side Air Distribution Duct
    G01482022Courtesy of GENERAL MOTORS CORP.
  10. Unclip the fuse block and position aside.
  11. Remove the 2 screws below the fuse block that hold the main harness connector to the cross vehicle beam.
  12. Remove the brake pedal. Refer to BRAKE PEDAL ASSEMBLY .
  13. Disconnect any ground wires, as necessary.
  14. Remove the nuts and bolts from the steering column support bracket.
  15. Remove the steering column support bracket from the cross vehicle beam.
    Fig 2: Unclipping Fuse Block
    G01482023Courtesy of GENERAL MOTORS CORP.
  16. Remove the retaining bolts and position the BCM bracket aside.
  17. Release the wiring harness retaining clips from the cross vehicle beam and position the wiring harness out of the way.
    Fig 3: Removing BCM Bracket & Retaining Bolts
    G01482024Courtesy of GENERAL MOTORS CORP.
  18. Remove the retaining bolts from the center support bracket of the HVAC module.
  19. Remove the center support bracket of the HVAC module.
    Fig 4: Removing HVAC Module Center Support Bracket
    G01482025Courtesy of GENERAL MOTORS CORP.
  20. Remove the retaining bolts from the upper support brackets of the HVAC module.
    Fig 5: Removing Retaining Bolts From Upper Support Brackets Of HVAC Module
    G01482026Courtesy of GENERAL MOTORS CORP.
  21. Remove the bolts which secure the left cross vehicle beam to the hinge pillar.
    Fig 6: Removing Bolts Securing Left Cross Vehicle Beam To Hinge Pillar
    G01482027Courtesy of GENERAL MOTORS CORP.
  22. Remove the bolts which secure the right cross vehicle beam to the hinge pillar.
    Fig 7: Removing Bolts Securing Right Cross Vehicle Beam To Hinge Pillar
    G01482028Courtesy of GENERAL MOTORS CORP.
  23. Remove the bolt (1) from the cross vehicle beam.
  24. Remove the cross vehicle beam from the vehicle.
    Fig 8: Removing Cross Vehicle Beam Bolt
    G01482029Courtesy of GENERAL MOTORS CORP.
  25. Remove the accumulator tube to evaporator core block fitting bolt.
  26. Disconnect the accumulator tube from the evaporator.
  27. Disconnect the evaporator tube from the evaporator.
  28. Remove the O-rings seals and discard.
    Fig 9: Removing Accumulator Tube To Evaporator Core Block Fitting Bolt
    G01482030Courtesy of GENERAL MOTORS CORP.
  29. Use J 38185  in order to position aside the heater hose inlet and outlet clamp at the heater core.
  30. Disconnect the inlet and outlet heater hose from the heater core.
  31. Disconnect the vacuum hoses from the HVAC module assembly.
  32. Disconnect the electrical connectors from the HVAC module assembly.
    Fig 10: Disconnecting Inlet & Outlet Heater Hose From Heater Core
    G01482031Courtesy of GENERAL MOTORS CORP.

    Important:  Position the heater core outlet cover downward and rearward in order to disconnect the cover from the rear area floor duct assembly.

  33. Remove the cover screws from the heater core outlet.
  34. Remove the cover from the heater core outlet.
    Fig 11: Removing Cover From Heater Core Outlet
    G01482032Courtesy of GENERAL MOTORS CORP.
  35. Remove the evaporator drain elbow.
    Fig 12: Removing Evaporator Drain Elbow
    G01482033Courtesy of GENERAL MOTORS CORP.
  36. Remove the nuts which secure the HVAC control module to the dash.
  37. Remove the HVAC control module.
    Fig 13: Removing Nuts Securing HVAC Control Module To Dash
    G01482034Courtesy of GENERAL MOTORS CORP.
  38. Remove all of the seals (1,2,3) from the outer HVAC control module.
Fig 14: Removing Seals From Outer HVAC Control Module
G01482035Courtesy of GENERAL MOTORS CORP.
RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.