One or more heater & AC (HVAC) temperature and/or air delivery mode door actuator may fail, resulting in improper temperature or air delivery. If this occurs, fault code(s) should be stored in the HVAC control module which should assist in diagnoses.Google+
Car Problem Reports
GMC Sierra 2500 Heating and AC Temperature and Air Delivery Mode Door Actuators May Fail
GMC Sierra 2500 Problem
Average Mileage: 91,775 mi (45,000 mi - 125,000 mi)
Visitor, 2003 GMC Sierra 2500, 105,326 mi
My 2003 2500HD is blowing extremely hot air out of the drivers side vents and the air conditioned air flows perfectly fine out of the passenger side vents. The dual temperature guages are working but it continues to blow very hot air just on the drivers side vents. If I stop, put the truck in park, turn the engine off, and then restart the engine then it will blow the correct cool air from the drivers side vents after about 3 times or so of repeating that process. I just had the compressor replaced about 6 months ago and was working fine, but now this strange thing is happening and I am not sure of the diagnosis.
Visitor, 2004 GMC Sierra 2500, 125,000 mi
ac will work and then blows hot air, restarting truck sometimes works
Visitor, 2004 GMC Sierra 2500, 45,000 mi
had to replace the heating actuator for the passenger side (duel control ) than the drivers side went, I have cold air in the winter and hot air in the summer, the local chevy garage , frenchies auto, wanted 400.00 dollars to replace it.
Visitor, 2004 GMC Sierra 2500
Only the drivers side is affected of the duel climate control. I have not yet fixed the problem, disconnecting the battery seems to be a short term fix.