GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Blazer - 2WD 🢒 HVAC 🢒 Heating, Ventilation and Air Conditioning 🢒 Heater/Vent Module Replacement

Removal Procedure
  1. Remove the instrument panel. Refer to Instrument Panel Carrier Replacement in Instrument Panel, Gages and Console.
  2. Drain the engine coolant. Refer to Cooling System Draining and Filling in Engine Cooling.
  3. Remove the blower motor resistor. Refer to Blower Motor Resistor Assembly Replacement .

    4. Object Number: 617623 Size: SH

    Important: Mark the mounting bolt from the heater/vent module for use during the installation process. Other mounting bolts are longer and will obstruct the operation of the temperature door.

  4. Remove the heat/vent module mounting bolt through the blower motor resistor or through the service access cover opening.
  5. Remove the right wheel house panel. Refer to Wheelhouse Panel Replacement in Body Front End.
  6. Remove the front right tire. Refer to Tire and Wheel Removal and Installation in Tires and Wheels.
  7. On the Utility only, remove the screws from the A/C evaporator and blower module heat shield.
  8. On the Utility only, slide the heat shield toward the front of the vehicle.

    9. Object Number: 1595 Size: SH
  9. Remove the 2 lower heat/vent module mounting nuts.
  10. On the Utility only, remove the heat shield bracket.
  11. Remove the mounting bolt to the bottom right heat/vent module from inside the vehicle.

    12. Important: The heat/vent mounting stud has a flange on the inside and cannot be removed from under the hood. Stop turning the stud after the threads are off the heat/vent module.

  12. On the Utility only, while an assistant inside the vehicle pulls the bottom right corner of the heat/vent module approximately 2.5 mm (1 in) back, remove the 2 heat/vent module mounting studs.
  13. Lower the vehicle.

    14. Object Number: 529580 Size: SH
  14. Remove the heater/vent module mounting bolt located at the lower left side of the connection between the heater core and the heater hose.
  15. Remove the heater/vent module mounting nut located at the lower right side of the connection between the heater core and the heater.

    16. Important: The heat/vent mounting stud has a flange on the inside and cannot be removed from under the hood. Stop turning the stud after the threads are off the heat/vent module.

  16. On the Utility only, loosen the heater/vent module mounting studs until the threads are free from the heat/vent module.
  17. Disconnect all of the electrical connectors from the heater/vent module.
  18. Disconnect all of the vacuum lines from the heater assembly.
  19. Disconnect the heater hoses from the heater core.
  20. Remove the heater/vent module from the vehicle.

Installation Procedure

    Object Number: 529580 Size: SH
  1. If you are replacing the heater/vent module, transfer the components from the old module as necessary.

    2. Important: Before installing the heater/vent module to the vehicle, ensure that the module mounting studs are located in the proper positions.

  2. Install the heater/vent module to the vehicle.
  3. Connect the heater hoses to the heater core.
  4. Connect all of the vacuum lines to the heater assembly.
  5. Connect all of the electrical connectors to the heater/vent module.
  6. Install the bottom right heater/vent module mounting bolt from inside the vehicle approximately halfway into the threads.

    7. Notice: Refer to Fastener Notice in the Preface section.

  7. On the Utility only, install the heater/vent module mounting stud, located at the lower right side of the heater core, to the heater hoses connection in the engine compartment.

    8. Tighten
    Tighten the stud to 4.5 N·m (40 lb in).

  8. Raise the vehicle.
  9. On the Utility only, install the bottom right heater/vent mounting studs. Ask an assistant to pull the bottom right corner of the heater/vent module back from inside the vehicle.

    10. Tighten
    Tighten the studs to 4.5 N·m (40 lb in).

  10. On the Utility only, install the A/C evaporator and blower module heat shield bracket.
  11. Install the heater/vent module mounting nuts.

    12. Tighten
    Tighten the nuts to 4.5 N·m (40 lb in).

  12. On the Utility only, slide the A/C evaporator and blower module heat shield into the original position.
  13. On the Utility only, install the screws to the heat shield.

    14. Tighten
    Tighten the screws to 2.2 N·m (19 lb in).


    Object Number: 1595 Size: SH
  14. Install the right front tire. Refer to Tire and Wheel Removal and Installation in Tires and Wheels.
  15. Install the mounting bolt to the bottom right heater/vent module from inside the vehicle.

    16. Tighten
    Tighten the bolt to 4.5 N·m (40 lb in).

  16. Install the right wheel house panel. Refer to Wheelhouse Panel Replacement in Body Front End.

    17. Object Number: 529580 Size: SH
  17. Install the heater/vent module mounting nut, located at the lower right side of the heater core, to heater connection.

    18. Tighten
    Tighten the nut to 4.5 N·m (40 lb in).

  18. Install the heater/vent module mounting bolt, located at the lower left side of the heater core, to heater hose connection.

    19. Tighten
    Tighten the bolt to 4.5 N·m (40 lb in).

    Important: Use the same mounting bolt marked during removal for the heater/vent module during the installation process. Other mounting bolts are longer and will obstruct the operation of the temperature door.

  19. Install the heater/vent module mounting bolt through the blower motor resistor or through the service access cover opening.

    20. Tighten
    Tighten the bolt to 4.5 N·m (40 lb in).


    Object Number: 617623 Size: SH
  20. Install the blower motor resistor. Refer to Blower Motor Resistor Assembly Replacement .
  21. Refill the engine coolant. Refer to Cooling System Draining and Filling in Engine Cooling.
  22. Install the instrument panel. Refer to Instrument Panel Carrier Replacement in Instrument Panel, Gages and Console.