HVAC blend door sticking

andyems · September 5, 2012

My 2007 GMT-900 had a problem last winter with I guess the blend door sticking when I was trying to get heat out of the vents. I'm guessing that was the problem and the right name of the part that sets the air temp coming out.

Anyway, the truck would be warm but it would only blow ice cold air. This happened 2-3 times, all several weeks apart. I forgot about it during the summer but now that winter is just around the corner I figure I should get it figured out.

Can anyone tell me how the hot/cold blend door works on the trucks. I just wondering if I'm having a mechanical problem with a flap, or maybe a vacuum leak causing it. I have an extended warranty but thought if it was an easy fix I'd do it myself and save the deductible. Thanks in advance for all the help.

txab · September 5, 2012

No vacuum. All electronic. Part alone is $100

andyems · November 9, 2013

Last winter (2012-13) this above mentioned problem (blowing cold air when the motor was warm) only happened one time. At the time I really couldn't afford to take it to the dealer and have them trouble shoot the problem. I figured if the part alone was around $100 it would be way more than that total. I didn't just replace the part because I didn't want to spend that much unless I was sure that was the problem. All summer it was not an issue again, and to he honest I had forgot about the problem and didn't think much about it. Fast forward to this morning. First frost of the year that I needed to use the defrost. Truck heated well this time, and blew hot air, but I could not get it to blow on the windshield. It would only blow on my feet or dash. I can hear noises behind the dash when I turn the selector, but it doesn't change to the defrost vent. Only dash and feet. Thinking since I now have 2 issues, it possibly is the control head, but again, don't want to spend that much unless I know that will fix the problem. Is there any way to trouble shoot this issue before I start swapping out parts? I want to fix it right the first time. Again it's a GMT-900 '07 Silverado with manual climate control.

txab · November 9, 2013

Get it scanned for codes. Someone with a tech II or equivalent

andyems · November 22, 2013

Just picked up my truck from the dealer. Replaced both the actuator for the temp control and the one that controls the flow direction. $615 +/- total. Only had to pay $51 after warranty paid its part! Warm air and defrost again! Awesome. Thanks for the help.