GM Service Manual Online
For 1990-2009 cars only

The HVAC control module will relearn the actuator limits whenever power is disconnected and re-connected to the module.

Use the following steps to perform the calibration update:

  1. Turn OFF the ignition.
  2. Remove the battery positive voltage circuit fuse of the HVAC Control Module.
  3. Important: The scan tool must be disconnected from the vehicle to properly perform the calibration procedure. If a scan tool is connected before this procedure is completed, then new calibration values will not be stored.

    Important: Failure to wait 60 seconds will not allow the HVAC control module sufficient time to clear the old calibration values.

  4. Wait 60 seconds.
  5. Install the fuse.
  6. Turn ON the ignition.
  7. Wait 60 seconds before installing a scan tool.