Heater help!!!!!

[Whorner76]

I'm hoping someone can give me some insight on my heater problems. I have a 2001 Chevy 2500hd. Crew cab 4x4 duramax diesel. The heat will only blow on the face setting. I can change the speeds and turn it off but that is all I can do. The buttons to turn on the rear defrost/heated mirrors won't work either. I also cannot adjust temperature. It will only blow hot air. The batteries on truck have been unhooked for the last week due to me changing injectors and installing a fass fuel system, not sure if the week of unhooked batteries had an effect on it or not. Please help. All advice is appreciated

[8.1HD/ALLISON]

Could be related to batteries, I would unhook again for an hour and then reconnect and try. If that doesnt work your going to need a wiring diagram and start tracing power and grounds. COuld be actuators, could be hvac control head, or any related wiring.

[Whorner76]

Okay. I'll try unhooking and rehooking batteries. Maybe that will do the trick

[txab]

http://www.gm-trucks.com/forums/topic/151483-ac-stuck-on-defrost/?p=1330898

[Whorner76]

Thanks for the help. Unhooking and rebooking batteries did the trick

[8.1HD/ALLISON]

No prob