I have tried recalibration several times and rear air still is hot and floor and overhead controls not working

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ID Status Date Year Make Model Transmission Type A/C Controls Public/Private
#15439 Closed 2012 GMC Yukon denali public

The problem started with rear ac blowing hot so I removed cowling to find that on 2012 GMC Yukon Denali has blend door actuators behind heater unit. I removed the ducking so I could see position of doors. After recal the floor control moved from top to bottom but then wouldn’t switch back to overhead and ac-heat door stayed on heat.
What should I do next? I put front and rear controls on auto but when I put fuse back in temp stayed at 74 but auto wasn’t lit and I hear or feel any action on blend door motors.
Sparky

Okay, I have been looking for the best way to recalibrate your rear system without a scan tool. The following is what is stated in GM service information. However, I believe that will only work for the front system. I have done some research and I think if you pull the radio RDO fuse #42 in the underhood fuse box instead of the HVAC/ECAS fuse it may work. You may have to disconnect the battery instead but I prefer not to do that as so many things will need to be relearned by the computer systems.

Alternate Method (w/o Scan Tool)

  1. Clear all DTCs.
  2. Place the ignition switch to the OFF position.
  3. Install the HVAC control module or HVAC actuator.
  4. Connect all previously disconnected components.
  5. Remove the HVAC/ECAS fuse for a minimum of 10 seconds.
  6. Install the HVAC/ECAS 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.

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