ID Status Date Year Make Model Transmission Type A/C Controls Public/Private
#14685 Closed 2008 GMC Sierra 1500 Denali public

I have 2008 GMC Sierra 1500 Denali. My A/C is blowing hot on the driver side and the passenger is blowing cold. Was not doing this until I replaced the alternator due to it going bad.


I would start with performing a system calibration. The procedure starts anytime battery voltage is removed from and reconnected to the HVAC control panel. Touching any button on the HVAC control panel while it is recalibrating will cause any actuator that was moving to become stuck in that position until a full recalibration is allowed to complete.

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.

Alternate Method (w/o Scan Tool)

  1. Place the ignition switch to the OFF position.
  2. Remove the HVAC Batt fuse in the underhood fuse box for a minimum of 10 seconds.
  3. Install the HVAC Batt fuse.
  4. Start the engine.
  5. Wait at least 40 seconds for the HVAC control module to self-calibrate.
  6. Turn the ignition off for at least 10 seconds but no more than 30 seconds.
  7. Start the engine and check the system controls.

Write a reply

The ticket has been closed. If you feel that your issue has not been solved yet or something new came up in relation to this ticket, you can re-open it by clicking this link.