Robert Picard

Was your problem full cold for everything including driver and passenger side and defroster? I tried two different actuators and even turned the door with my fingers and it was still nothing but cold air.

In trying to get some heat, I have changed pretty much everything in my 05 Sierra's HVAC system except for the cabin air sensor aspirator. I tried to search YouTube for location of that unit and all I can find is the one with the little speaker type grille in the headliner over the driver's head. I have a single cab and nowhere on the entire headliner can I see anything that looks like what's on YouTube. Where is it located so I can replace it wit a new one?

Thank You

I can't figure out how to reply to individual posts in this forum. For SHARPZ as I have noted in my original post, I have tried all of what you have suggested to no avail. The Thermostat was changed a short time ago and the temp gauge shows normal operation. For PopeyeD, I have not considered that option. Where specifically is the cabin air temperature sensor aspirator located. You mentioned over the driver's seat is it under the headliner? or behind some plastic panel that I need to remove? I have a single cab model if that makes any difference. Bob

My 2005 Sierra's HVAC is stuck in the cold mode. As another Alaska winter is approaching I'd sure like to have it fixed before it arrives. I have gone as far as I could with all that I've been able to gather so far on you tube and it still doesn't work. AC works fine I just can't get it to put out heat. I have changed all the mode door actuators (even the almost impossible to get to one where almost the entire dashboard has to be removed) except for the air recirc one which I verified works by cycling it. The mode selector was also changed and was verified to work with the proper selection of defrost, foot air, upper air etc. I changed the control panel (the one with the two knobs on either side with the vertical temperature slide levers in between) with a used one I got from ebay. I am not able to test the used unit that I bought but I would think that both control panels wouldn't have the same failure unless that is a common issue with these units. I did the pull-the-fuse re-calibration of the system as explained on you tube. I even had the cooling system flushed and the heater core back-flushed just in case there was blockage. The system was pretty much clean, still no heat. not even a little. Is there a magic control box somewhere that I may have missed? Where to next? Cold in Alaska Bob