A/C problem on 07 GMC
 

I've got an 07 GMC Sierra and every now and then the A/C will just start blowing hot, not warm, hot. But if you turn the temp adjust dial from cold all the way to hot and back to cold, it will start blowing cold again. Sounds like something with the dial. I had problems with the #1 speed on the blower dial on my 07 chevy and it turned out to be a resistor for that speed. Hopefully this is something similar and easy to fix. Thanks for any help yall can give me.

Re: A/C problem on 07 GMC
 

I'm assuming it's an 07 classic. Its most likely the temp control actuator. If its the drivers side it's on the bottom of the AC case under the insulator panel. Quick fix that sometimes works permanently is to recalibrate the AC controller by removing the HVAC/ECAS for 30 seconds with the ignition off, reinstall the fuse, then start the truck and allow it to run for a minute without touching A/C controls. If it doesn't recalibrate and gets stuck in hot you'll need a new temp door actuator.

Re: A/C problem on 07 GMC
 

Actually, it's the newer body style. And it doesn't have the dual climate control. It's the Sierra SLE.