SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSCHEVROLET2003TRAILBLAZER 4.2 S, 4WDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 1443 (HVAC SYSTEMS - GENERAL SERVICING)REPAIR INSTRUCTIONSHVAC MODULE REPLACEMENT - AUXILIARYINSTALLATION PROCEDURE
2003 Chevrolet TrailBlazer 4.2 S, 4WD

Installation Procedure

2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Installation Procedure
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2004 Oldsmobile Bravada, 2004 GMC Envoy XUV, 2004 GMC Envoy XL, 2004 GMC Envoy, and 2004 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
  1. Install new HVAC module pass through seal. Refer to HVAC Module Pass Thru Seal Replacement - Auxiliary .
    2. Fig 1: Auxiliary HVAC Module
    GM735953Courtesy of GENERAL MOTORS CORP.
  2. Install the HVAC module (1).
    3. NOTE: Refer to FASTENER NOTICE in Cautions and Notices.
  3. Install the HVAC module mounting bolts (5).

    Tighten:  Tighten the bolts to 10 N.m (89 lb in).

    4. Fig 2: Rear Ducting Views
    GM735895Courtesy of GENERAL MOTORS CORP.
  4. Install the air outlet ducts (5).
  5. Connect the electrical connectors.
  6. Install the right side rear quarter trim panel. Refer to Trim Panel Replacement - Rear Quarter - Right (TrailBlazer, Envoy, Bravada) or Trim Panel Replacement - Rear Quarter - Right (TrailBlazer EXT, Envoy XL) in Interior Trim.
  7. Raise and support the vehicle.
    8. Fig 3: Auxiliary Heater Hose Block Fittings
    GM400657Courtesy of GENERAL MOTORS CORP.
  8. Connect the heater hoses to the heater core.
  9. Install the nuts to the HVAC module studs.

    Tighten:  Tighten the nuts to 10 N.m (89 lb in).

  10. Remove the cap or tape from the A/C lines.
  11. Install the new O-ring seals. Refer to O-Ring Replacement .
    12. Fig 4: Rear A/C Line Block Fittings
    GM735776Courtesy of GENERAL MOTORS CORP.
  12. Install the nuts (3) to the evaporator core studs.

    Tighten:  Tighten the nuts to 20 N.m (15 lb ft).

  13. Lower the vehicle.
  14. Fill the cooling system. Refer to Draining and Filling Cooling System (LL8) or Draining and Filling Cooling System (LM4) in Engine Cooling.
  15. Evacuate and charge the system. Refer to Refrigerant Recovery and Recharging .
  16. Leak test the fittings of the components using the J 39400-A  . See Special Tools and Equipment .
RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

Shop Manual-Ready ToolsFree Quote CheckQuote Shield Pro

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.