Hey guys my A/C and heater both malfunction sometimes. Whenever, I turn my A/C on it works fine but after a few minutes it blows hot air instead of cold air but only on the drivers and rear passenger side. Meanwhile the front passenger works perfectly fine. It does the same thing for the heater. Turn it to cold it blows warm air, turn it to the heater it blows cold (only in the winter lol). Does this happen to anybody else? Thanks for any inputs in advance.

 

This is a common issue when the blend door actuators malfunction. Search the forums for blend door actuators. I had a similar issue where my drivers side blew cold but my passengers side blew hot with the A/C on and both sides set to 60. I had to take the dash apart and replace the blend door actuator behind the glove box underneath the top of the dash.

 

Is the drivers side and the rear passenger side use the same blend door actuator and thank you for your reply I really appreciate it.

 

Read over this thread it should have all the answers you're looking for:
https://www.hummerforums.com/forum/h...answers-27779/
If not, report back