GM Service Manual Online
For 1990-2009 cars only

When replacing the HVAC control module it will be necessary to allow the HVAC control module to perform a calibration process. When installing the HVAC control module be sure to perform the following:

Important: Do not adjust any controls on the HVAC control module while the HVAC control module is self-calibrating. If interrupted, improper HVAC performance will result.

  1. Place the ignition switch to the OFF position.
  2. Disconnect the scan tool.
  3. Install the HVAC control module.
  4. Connect all previously disconnected components.
  5. Start the vehicle.
  6. Wait 40 seconds for the HVAC control module to self-calibrate.
  7. Verify that no DTCs have set as current DTCs.

When replacing the HVAC actuator it will be necessary to allow the HVAC control module to perform a calibration process. When installing the HVAC actuator be sure to perform the following:

Important: Do not adjust any controls on the HVAC control module while the HVAC control module is self-calibrating. If interrupted improper HVAC performance will result.

Calibration Procedure

  1. Clear all DTCs.
  2. Place the ignition switch to the OFF position.
  3. Install the HVAC actuator.
  4. Connect all previously disconnected components.
  5. Remove the HVAC (BATT) fuse for a minimum of 10 seconds.
  6. Install the HVAC (BATT) fuse.
  7. Start the vehicle.
  8. Wait 40 seconds for the HVAC control module to self-calibrate.
  9. Verify that no DTCs have set as current DTCs.