2005 GMC Sierra 2500HD SLT 4X4 CCSB / 6.6 Duramax / Allison 1000 / S&B Mouthpiece / 4" MBRP
Here's a link to a thread I started. You'll learn a good bit.Climate control problem. I only have hot air when I put the thermostat at 90°. I don't have any cold air from a/c.
I thought I would make a post here to sort of track what issues I've had with my truck's HVAC systems recently. It all started when I dimmed my dash lights with the dimmer switch. Everything worked exactly as it should until I put the switch all the way to the bottom of it's range and the dash...
More than likely your cabin temperature sensor above your left ear is bad. You can try resetting the HVAC control unit like I did in the thread if you have dual zone AC. If you have the manual dual zone then I have no idea. Good luck.