The topic of how to perform the actuator recalibration procedure on Chevrolet , GMC and Cadillac Trucks and SUVs has become an ever increasing topic of discussion.
For manual systems it does not matter where the a/c controls are set but if you feel the need to do something, turn the blower switch on (I prefer speed 3) and set the temperature sliders about .5″ to .75″ from full cold.
For auto systems, press the auto button, with the key on.
Turn the ignition off.
Remove the HVAC/ECAS , 10 amp fuse in the underhood fuse box* or disconnect the battery for one minute.
*Fuse locations can vary from year to year and between different models. Hopefully I will be able to build a list for this.
Install the HVAC fuse or reconnect the battery.
Start the engine. On systems with auto a/c controls the controls will default to 74 degrees F when the ignition is turned back on.
DO NOT TOUCH the a/c controls.
Let the engine run for 1-2 minutes.
Turn the ignition off for at least 10 seconds but no more than 30 seconds.
Restart the engine and then test the a/c controls.
I have a 2008 Sierra Denali that is having AC issues. It started out with driver side would blow hot air only occasionally. I replaced the main controller mainly because it looked terrible because all the pain had come off. So now I no longer have the driver side hot air issue but now I lose all air through all vents on occasion. I can hear the blower running but I can’t get any air our of any vents at all. I sounds like it is stopped up. This only happens every once in a while and drives me crazy. I have pulled the battery cable several times trying to perform a relearn. I do not see this HVAC/ECAS fuse on my 08. Any help would be appreciated.
I am including links to two articles that I did regarding your probable issue. Be sure to use the search features within this site and also use the “Sparky’s Repair Article Menu” tab near the top left of the page.
http://www.sparkys-answers.com/2012/01/2003-chevrolet-trailblazer-clicking.html
http://www.sparkys-answers.com/2012/01/2003-chevrolet-trailblazer-changing.html
I also rear that it could be an actuator. Not sure which one and where they’re all located.
I have a 2006 GMC Envoy XLT. When I turn on the rear heater it only blows cold air from the floor vents and no air from the over head vents. The overhead vents does not work either when the a/c is on. I also hear a clicking noise in the rear right 3rd row of seats. Not sure if that’s part of the HVAC system. And it seems like there’s a draft somewhere in the front. I hope that’s enough info to help me with this problem. I highly appreciate it if you can help me with this.
No one else reads that so ask away.