HVAC Actuator Recalibration Procedure For GM Trucks and SUVs

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.

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*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.

301 discussions on “HVAC Actuator Recalibration Procedure For GM Trucks and SUVs”

  1. Hi sparky, i have a 2005 yukon denali xl with the auto air conditioner with the same problem. Drivers side blows hot air. Ive tried the above tips with no luck. Any advice to my specific vehicle? Thanks!!

      1. Assuming that you removed and replaced the HVAC fuse in the instrument panel fuse box to initialize the recalibration then the next step would be to replace the driver’s side temperature door actuator.

        1. Thanks for your help on this. Looks like I’ll have to replace it. Do you know if any good youtube videos showing replacement of drivers side? (Traverse) Any tips would be great.

          Thanks again Sparky!

      1. Oddly enough, when I got home and ready to do this, I started the Tahoe and miraculously the A/C is blowing cold. Maybe it re-calibrated on it’s own, lol. Had no further issues yesterday driving around. Thanks for the quick response regardless!

  3. Could you please help me find the correct fuse in a 2010 Buick Enclave. I had the battery unplugged for about 2weeks while I put on new timing chains. When I hooked the battery back up after the job the drivers side blow hot and passenger blows cold. Any help would be greatly appreciated.

      1. When I do this mine doesn’t default to 74. The temp is the same it was before I pulled the fuse. Should I leave the ignition key in and turned on Just not started? I turn the car off and removed the key when I removed the fuse for a little over a minute. I then put the fuse back in, inserted the key and started the car. I waited for 2 min but the drivers side was on hot the whole time. I then turned the car off and started it again and it’s still hot. I’ve replaced the actuator with a new one but same results. I can remove the actuator but leave it plugged in and the motor will always move all the way to the same side which is the hot side if it was mounted. Any advice? Thank you.

          2. I would probably disconnect the battery instead of removing the fuse if you have not had any success. Please move this discussion over the the Ask a Question part of the site. It is too difficult to follow if it goes past one reply in the comments.

  4. I have a 2001 Chevy Suburban 1500. Ice cold air in the rear, warm in the front. I can’t find a fuse that says “HVAC/ECAS” I’ve tried doing this with every other fuse that says “HVAC” or “A/C”. No luck. I can get air to come out the defrost, the upper vents, and the floor vents. I just can’t get the air temp to change at all. I bought a new actuator for the hot/cold door, and it’s moved when I do this sometimes, but now it’s just stuck. The old door was doing the same thing, though. I’m at a loss.

    1. Unless your Suburban has Auto a/c controls there is not a procedure for recalibrating any of the actuators on that year model. Was the new actuator installed before testing it or was it just hanging and plugged in to check?

      1. I just had it hanging and plugged to check at first. It’s installed now (just to keep the door open to the cool side and not flopping back and forth). The air is still not cold like it is in the back.

        My a/c controls include three dials. (1) Blower speed dial, which includes an “auto” setting. (2) Computer temp control dial, including full cold and full heat settings. (3) Dial to control which vents air comes through (head, feet, defrost), and which also includes an “auto” setting. Not sure if that means I have auto controls or not, but I’m assuming yes?

        1. Since you have Auto controls there is a procedure for recalibrating the actuators.

          The HVAC control module will relearn the actuator limits whenever power is disconnected and re-connected to the module.

          Use the following steps to perform the calibration update:

          •Turn OFF the ignition.
          •Remove the battery positive voltage circuit fuse of the HVAC Control Module. On your vehicle it is the Radio fuse in the underhood fuse box.

          Important: Scan tools must be disconnected and do not touch any control other than the ignition switch until the process is complete.

          Important: Failure to wait 60 seconds will not allow the HVAC control module sufficient time to clear the old calibration values.
          •Wait 60 seconds.
          •Install the fuse.
          •Turn ON the ignition.
          •Wait 60 seconds.Turn the ignition off for at least ten seconds but no more than 30 seconds. Start the engine and test the functions.

          2. According to GM service information it can only be done with a scan tool. Looking at the wiring diagrams if a fuse were to be used it would have to be the RVS/HVAC/DLC fuse in the interior fuse box.

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