GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2000 🢒 Montana 🢒 Engine 🢒 Engine Electrical 🢒 HVAC Module Assembly Replacement

Removal Procedure
  1. Drain the cooling system. Refer to Cooling System Draining and Filling in Engine Cooling.
  2. Recover the refrigerant. Refer to Refrigerant Recovery and Recharging .
  3. Remove the body hinge pillar tie bar-cross car beam. Refer to Instrument Panel Tie Bar Replacement in Instrument Panel, Gauges, and Console.

    4. Object Number: 392579 Size: SH
  4. Disconnect the A/C lines at the evaporator block fitting.

    5. Object Number: 392563 Size: SH
  5. Disconnect the heater hoses at the heater core.

    6. Object Number: 392551 Size: SH
  6. Remove the heater A/C module to dash nuts.
  7. Remove the heater A/C module bracket bolts.
  8. Remove the vacuum hoses.
  9. Disconnect the electrical connectors.
  10. Remove the heater A/C module.

    11. Object Number: 179036 Size: SH
  11. Remove the outer module seals.

Installation Procedure

    Object Number: 179036 Size: SH
  1. Install all of the outer module seals.

    2. Object Number: 392551 Size: SH
  2. Install the heater A/C module.
  3. Connect the electrical connectors.
  4. Install the vacuum hoses.

    5. 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.

  5. Install the heater A/C module bracket bolts.

    6. Tighten
    Tighten the bolts to 20 N·m (14 lb ft).

  6. Install the heater A/C module to dash nuts.

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


    Object Number: 392563 Size: SH
  7. Install the heater hoses at the heater core.

    8. Object Number: 392579 Size: SH
  8. Connect the A/C lines at the evaporator block fittings.

    9. Tighten
    Tighten the bolt to 16 N·m (12 lb ft).

  9. Install the body hinge pillar tie bar-cross car beam. Refer to Instrument Panel Tie Bar Replacement in Instrument Panel, Gauges and Console.
  10. Evacuate, charge and leak test the system. Refer to Refrigerant Recovery and Recharging .
  11. Fill the coolant system. Inspect the coolant system for leaks. Refer to Cooling System Draining and Filling in Engine Cooling.