2011 Chevy Tahoe Z71 Climate Control Problems

[Bamafan]

Hello All, Having problems with my 2011 Tahoe Z71 AC Climate Control.
First of all when the car has been sitting for an extended period of time the AC works great, no problems at all. I have checked the controls when it is working fine and all controls appear to be working exactly as they should, Auto and Manual, vents swap properly, temperature changes properly. After I have driven it for a while, I would say approximately 30 to 60 minutes the problem starts. The drivers side stays cold and the passengers side will start oscillating between cold and hot, mostly hot. Also the vents start oscillating. If the vents are set to dash the drivers side and passengers side will start swapping from the dash vent to the floor vents back and forth. Does this whether in Pass control or not. If I swap the vent to the floor it starts swapping from the defrost to the floor back and forth. Does this whether in automatic or manual. If I turn the car off and back on the problem remains. It has to sit for a while for it to start working properly again. Not sure really how long. Any ideas? Thanks in advance for any help on this.

 

[Bamafan]

2011 Tahoe Z71 AC Problems

So to follow up on what I found. Since I was having problems with 2 actuators and both started having problems at the same time and it would only happen after the car was driven for a while and things heated up I figured it was a problem with the Heater A/C Controller. I replaced it and got an original AC Delco from Ebay for $138.00. After replacement I still had problems with one of the actuators. The mode door actuator wouldn't calibrate and work properly. I replaced it and it immediately calibrated and have had no problems for a week now. I personally think the Heater A/C controller was the original problem, but with the Vent Actuator swapping back and forth between defrost and vent for a long period of time before I figured out the problem it messed up the actuator. Most of the internals are plastic. Hope this helps someone. I'm also including a link that will show the locations of the Actuators. At the end of the document it will show the locations. If you have to replace the Mode door actuator (vents, floor, defrost) you have to go in under the drivers side.

Heater A/C controller part number 15-74023 $138.00
(All digital and pushbutton no knobs)
HVAC Panel Mode Door Actuator 15-73952 $53.75

https://www.2carpros.com/articles/replace-blend-door-motor