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.
Hi sparky. I have a question but not sure how to ask you. Says this comment box are only for comments and not for questions. Thank you. Alfred
Hi Chris,
Through a little bit of trial and error, you can remove the actuator and disassemble it. Re index the actuator shaft so that the door is turned to heat. Install the actuator and leave the harness disconnected.
Sparky,
You were right, the coolant was a bit low so I added some more and re-did the calibration procedure again. I’ve driven about 100 miles since then and haven’t noticed any change in air temperature.
Is there anything I can do in the meantime to get my heater to work? The new parts should be in later this week but.
Thanks,
Chris
Before you do anything else, check the coolant level. What you have described may be an engine cooling system that is down half a gallon or more in coolant but not low enough to affect the engine.
Hi Sparky,
I’m having blend door issues with my 2004 gmc Yukon 5.3L with digital auto climate controls. Everything is working fine except that the driver side vents only blow cold air, and the rear vents occasionally only blow cold air.
I’ve tried the re-calibration procedure four times (even tried pulling the ECC fuse for the rear) and checked the connections at the passenger side junction box, but all to no avail.
I decided to go ahead and replace the driver side blend door actuator today but it turns out I ordered the air mode actuator by mistake (Dorman 604-112 instead of 604-106), so I sent it back and am waiting on the correct part to arrive. To make things even more interesting, the rear vents have now decided to only blow cold air as well, leaving just the two passenger vents for heat.
Are you aware of any way to manually set the actuators to only put out hot air? It’s going to be a few days before the new parts come in the mail and it’s absolutely freezing here in Colorado! Any input is much appreciated.
TIA,
Chris