GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 1998 🢒 Catera 🢒 HVAC 🢒 HVAC Systems - Automatic 🢒 HVAC Module Assembly Replacement

Removal Procedure
  1. Recover the refrigerant. Refer to Refrigerant Recovery and Recharging .
  2. Disconnect the battery negative cable.
  3. Drain the cooling system. Refer to Cooling System Draining and Filling .

    4. Object Number: 309505 Size: SH
  4. Remove the heater hose quick connects from the heater core pipes:
    5. • Raise the air inlet screen on the passenger side and open the access door near the pollen filter.
    • Squeeze the tabs on the locking collar and pull back on the sleeve in order to unlock.
    • Carefully pull back the tabs in order to remove the disconnects.
    • Discard the green assembly markers (1) if attached.

    Object Number: 153145 Size: SH
  5. Remove the evaporator line extension bolt from the cowl.
  6. Remove the steering column. Refer to Steering Column Replacement .
  7. Remove the I/P carrier. Refer to Instrument Panel Carrier Replacement in Instrument Panel, Gauges and Console.

    8. Object Number: 153286 Size: SH
  8. Remove the vacuum line connection at the cowl.

    9. Object Number: 153150 Size: SH
  9. Disconnect the electrically operated actuator connectors.

    10. Object Number: 153279 Size: SH
  10. Remove the heater core pipe bracket screw.
  11. Remove the heater core pipe bracket.

    12. Object Number: 153280 Size: SH
  12. Remove the heater core inlet and outlet pipe retaining bracket screw.
  13. Remove the heater core inlet and outlet pipes.

    14. Object Number: 153281 Size: SH
  14. Remove the I/P support brace bolt from the I/P.
  15. Remove the I/P support brace bolt from the transmission well.
  16. Remove the I/P support brace.
  17. Remove the following components from the vacuum actuators:
    18. • The vacuum hoses
    • The electrical connections

    Object Number: 153287 Size: SH
  18. Remove the two air distribution module engine compartment screws.

    19. Object Number: 153288 Size: SH
  19. Remove the module interior nut.

    20. Object Number: 153289 Size: SH
  20. Remove the LH/RH floor rear supply duct screws from the module.
  21. Remove the ducts from the module.
  22. Reposition the wiring harness in order to allow the removal of the module.

    23. Object Number: 153290 Size: SH
  23. Remove the module:
    24. • Carefully lift the upper vents from under the rubber seal.
    • Angle the module outward in order to remove.

Installation Procedure

    Object Number: 153290 Size: SH
  1. Install the air distribution module.
  2. Position the wiring harness in order to facilitate the I/P carrier installation.

    3. Object Number: 153289 Size: SH
  3. Install the RH/LH floor rear supply ducts.
  4. Install the duct screws until fully seated and not stripped.

    5. Object Number: 153288 Size: SH

    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 module interior nut.

    6. Tighten
    Tighten the module interior nut to 4 N·m (35 lb in).


    Object Number: 153287 Size: SH
  6. Install the module engine compartment screws.

    7. Tighten
    Tighten the screws to 4 N·m (35 lb in).

  7. Install the following vacuum actuator components:
    8. • The electrical connections
    • The hoses

    Object Number: 153281 Size: SH
  8. Position the I/P support brace at the I/P and at the transmission well.
  9. Install the I/P support brace bolts at the I/P and at the transmission well.

    10. Tighten
    Tighten the bolts to 22 N·m (16 lb ft).


    Object Number: 153280 Size: SH
  10. Install the heater core inlet and outlet pipes:
    11. • Use new O-rings.
    • Lightly lubricate the O-rings with coolant.
  11. Install the heater core inlet and outlet pipe retaining bracket screw.

    12. Tighten
    Tighten the screw to 5 N·m (44 lb in).


    Object Number: 153279 Size: SH
  12. Install the heater core pipe bracket.
  13. Install the heater core pipe bracket screw until fully seated and not stripped.
  14. Connect the electrically operated actuator connectors.

    15. Object Number: 153286 Size: SH
  15. Connect the vacuum line connection at the cowl.
  16. Install the I/P carrier. Refer to Instrument Panel Carrier Replacement in Instrument Panel, Gauges and Console.
  17. Install the steering column. Refer to Steering Column Replacement .

    18. Object Number: 153142 Size: SH
  18. Install the evaporator line extension bolt to the cowl.

    19. Tighten
    Tighten the bolt to 20 N·m (15 lb ft).


    Object Number: 309508 Size: SH
  19. Install the heater hose quick connects to the heater core pipe connections:
    20. • Discard green assembly marker (1) if not attached to the quick connect.
    • Inspect that the quick connects are fully seated.
    • Squeeze the locking tabs (2) and push the retaining sleeve (3) into the locked position.
    • Close the access door near the pollen filter and lower the air inlet screen on the passenger side.
  20. Fill the cooling system. Refer to Cooling System Draining and Filling .
  21. Connect the battery negative cable.
  22. Reprogram applicable accessories.
  23. Evacuate and recharge the A/C system. Refer to Refrigerant Recovery and Recharging .
  24. Leak test the A/C system.