Climate Control Temperature Issue.

jsoden · January 30, 2011

New to the forum, and I have a problem I'm hoping someone can help me with. I have a 2000 GMC Sierra 1500 SLE. I love this truck, but am experiencing a problem with it. I just purchased it a few weeks ago (couldn't check the temp because it's been cold here.) When driving, I turned the temperature control from warm to cold when it got warm out and nothing happened. Had to drive with the window down because the warm air kept coming through. I thought it was maybe low on coolant or had a blown fuse. I stopped and pulled all the HVAC fuses and all were good. I started it up, and the air became cold. However, when I jumped on the interstate, it got warm again. I think this is due to low coolant level. When I got into the truck later and started it, it was blowing cool outside air now. As we drove north, it got cold out, so I turned it to WARM, and it stayed cold. I tried everything and it kept blowing cold. About halfway through the trip, I started playing with the knobs again and turning the temp knob back and forth. I turned the blower up to 2 and it finally kicked over to warm. Does anyone know what this is? I thought maybe it was the temp actuator door sticking or not working right. If so, does anyone know where mine is located?? Any help would be GREATLY appreciated. Also, my auto parts store has the same part (one for 45 bucks, the other for 150) that is a blend door actuator. However, one says "Upper" and the other says "bottom". Does my truck have two? Which one do I need? No one can seem to tell me.

jsoden · February 1, 2011

Ok. I got it figured out thanks to the people at O'reilleys auto parts. This job was fairly simple and only took me about 30 minutes total. The hardest part was that one pain in the a## screw above the transmission hump putting the hush panel back on. When you do NOT have dual climate control, your one temperature actuator is located under the passenger side dashboard behind the hush panel underneath. It is just above the right side of the transmission hump. Three screws and the hush panel was off. Two screws and the actuator comes down and out. Then all you have to do is unplug it. There is very little clearance, so it might take some coaxing. I was able to manually turn the new actuator with a socket wrench with NO socket on it. (the square fit right in) This helped me line it up so it would fit back on. Once the new one is in place, do NOT turn it on yet. I pulled the HVAC and HEATER/AC fuses from the panel by the drivers side door, as well as the HVAC fuse in the fuse box under the hood on the drivers side. Leave them out for at least 30 minutes. This resets the HVAC system. When the time has passed, replace the fuses and turn the trucks ignition to ON, but do not start it. Leave your HVAC system alone for a few minutes. I guess it self-programs and figures out how far the actuator is supposed to turn. After this, I fired it up and played with it for awhile and everything worked perfectly!! When looking for parts for this job, there are two to choose from. UPPER and BOTTOM. Purchase the BOTTOM! It's the correct part and it's the cheap one! Cost me about 50 bucks and only took 30 minutes. MUCH better than the 700 dollar quote from the dealership! I just hope this helps someone else in my predicament!