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.


*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. I have a 2006 Chevrolet Equinox. One day my AC stopped blowing cold air. Everything with the AC was working fine (compressors etc) however, the vents were blowing HOT air. Not just outside temp air, but HEATED air, it was as if the system thought I had turned the heat on. I replaced the actual knob and actually the whole front piece where all the knobs are and the plugs connect, and still, it was blowing HOT air no matter where the temp control knob was turned. In this car there is only one knob.

    The other day all of a sudden I have super cold air (Again, as if this time the car believed I had the AC on. And that’s where I’m at now, only blowing cold air, even if I turn the temp knob to heat, I’m only getting ice cold air now.

    Cold weather is approaching soon and I’ll need heat, so researching, I’ve found it’s either the blend door itself, the actuator, or it needs recalibrated. Which brought me here.

    I the 06 Equinox there isn’t the exact fuse that you have described, as far as fuses go I have (BCM/Hvac, and HVAC BLOWER) and then for relays there is one also named HVAC BLOWER.

    I may not be seeing the right fuse, but that’s all I’m seeing when it comes to anything to do with HVAC.

    My question, is to do this procedure to recalibrate the actuator or blend door, which fuse should I pull to do it with? Maybe there’s another fuse I didn’t list that would do it, but those are the only fuses and relays that have HVAC in the name.

    Again it’s an 06 Equinox LS

    Thank you! I’d hate to have to try to replace the actuator or the blend door itself, so I’d like to try to do this procedure first. Thank you again.

    1. The following procedure was found in GM service information. Hope it helps.

      Actuator Recalibration
      When replacing the HVAC control module it will be necessary to allow the HVAC control module to perform a calibration process. When installing the HVAC control module be sure to perform the following:

      Important: Do not adjust any controls on the HVAC control module while the HVAC control module is self-calibrating. If interrupted, improper HVAC performance will result.

      Use the following steps to perform the calibration update:

      Ignition in ON position or engine running.
      Simultaneously press the A/C and recirculation buttons on control head 3 times in less than 2 seconds.
      The Mode setting lights will flash during calibration and will quit flashing once calibration is completed.
      This calibration process can take up to 30 seconds.

  2. I have a 2016 Ford Transit 3.7 and I want to recalibrate the actuators but the scan tool doesn’t have that option for this vehicle and I found this page where you could manually do it with a fuse. I can’t find the fuse in your example so is there a different one I should do it with? THANK YOU

  3. Sir,
    I have a 2015 Equinox LTZ. The HVAC control has an auto button.
    I replaced the mode actuator door. Because it isn’t working correctly I attempted several times and several methods to recalibrate.
    The new actuator door is moving as I go through the different modes but not reaching the full range to engage defrost only. Dorman replacement part.

    1. Alternate Method (without Scan Tool)
      Note: Do not operate any HVAC controls while the HVAC control module is calibrating as this may interrupt the process. If interrupted, improper HVAC performance will result.

      Ignition OFF/ Vehicle OFF.
      Remove the HVAC BATT fuse for a minimum of 10 s.
      Install the HVAC BATT fuse.
      Start the vehicle.
      Wait at least 40 seconds for the HVAC control module to self-calibrate.
      Turn the ignition off for at least 10 seconds but no longer than 30 seconds.
      Restart the engine and check system operation.

      The HVAC BATT fuse is located in the interior fuse box.

      What is the part number of the replacement actuator?

      1. I have a 2002 Chevrolet Suburban. My front ac is blowing out of the defrost the directional module is brand new. My system has the 3 knobs, blower knob says auto with a bunch of dashes after, then temp and then position knob with auto followed by dash and so on. What fuse should I pull to initiate the recalibration? Of course this would happen when it’s starting to get hot in Florida

        1. In your vehicle it would be the Radio fuse in the underhood fuse box.

          The following is from GM Service Information.

          Actuator Recalibration
          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.

          Important: The scan tool must be disconnected from the vehicle to properly perform the calibration procedure. If a scan tool is connected before this procedure is completed, then new calibration values will not be stored.

          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 before installing a scan tool.

      1. That appears to be the correct part even though it is not my favorite brand. Without a scan tool there is not a lot you can do but I would suggest you feel or watch the other actuators while the recalibration is being performed. Here is the reason. There is a sequence to the recalibration and if any actuator fails to recalibrate, it is halted. So if any of the other actuators were to fail and they come before the mode actuator in the sequence, then the mode actuator will not even get a chance to recalibrate.

        1. Thank you for your response, I have not gotten the car scanned yet. New problem, likely do too messing with the fuses so many times. Now my back up camera does not display video, it does display back up guidelines . And my dome lights are not working. Can you point me to a likely a blown fuse or relay. I did check my 5 amp camera fuse under the hood, that was not the problem.

          1. BCM6 was the culprit. Thank you for saving me time and money.
            I’m assuming the standard OBD2 reader/scanner that autozone does for free would not be sophisticated enough to calibrate the mode actuator separate from the others. Am I correct in that assumption?

  4. Hello. I have a 2003 Tahoe z71. The front AC works fine. It’s a digital one and it has the abilities to go from hot to cold and also change settings from feet to head.

    However, my rear AC is a different story. On the rear AC, I have the capability to change the fan settings along with changing the amount of air is pushed between the head and feet just fine. The temperature setting between hot and cold, I am unable to change. The temperature it’s not blowing hot, neither it’s blowing cold. It seems as if the compressor is not working, however it is as the front AC works just fine. What can it be? Thanks.

    1. The front and rear systems share the same compressor. I would recommend the following. Start the engine and run the a/c for several minutes. Open the hood and locate the a/c suction lines on the passenger side of the vehicle. The main suction line will be attached to the accumulator tank. follow it back to locate the “Y” that goes to the rear of the vehicle. All three legs of the “Y” should be equally cold and sweating. Next, confirm the transmission shifter is fully in park. Set the parking brake and chock the rear wheel against rearward movement. Lay on the ground parallel to the side of the vehicle at the passenger rear of the vehicle. Locate the a/c lines(one small and one large). The larger line should be cold and sweating. The small one should be warm/hot(use a light quick touch at first to confirm it will not burn you). If all of that tests as okay you likely have a problem with the rear temperature blend door actuator. If the rear suction line is not cold and sweating then either the refrigerant charge is low or the rear expansion valve is faulty/blocked. However, I do not recommend just trying to top off the refrigerant system as a test. The refrigerant charge level has to be accurate to work properly and this can only be done by measuring the refrigerant weight.

          1. Thank you for the knowledgeable information and swift reply. I will do what you advise and will report findings!

  5. The rear air system in my 2004 Chevy Suburban 1500 LT is blowing warm/hot on the max cold AC setting (driver’s rear controls by rear view mirror set to auto blower/max cold temp/auto bilevel). The blower and the bilevel seem to be working just fine. With the rear air blowing warm/hot on the max cold temp setting (overhead driver’s rear controls), I can change the temp setting to max hot and, over the span of about 10-15 second the air will blow hot to warm to “cool” then back to hot. That suggests to me that the actuator might be working and is just out of calibration.

    My main question is – does Sparky’s actuator calibration procedure work for the rear air system, as well? Do I need to do anything special to get the rear system to calibrate? After multiple calibration attempts using the above procedure, I don’t get any change on the rear system (although I did somehow get the front to blow hot and had to do multiple attempts just to get things back to where I started).

    Thanks …

    1. GM does not list a recalibration procedure for the rear system. If you wanted to try something you could do the procedure you have already tried but using the ECC fuse in the interior fuse box instead of the fuse listed in the article. Most likely you will need to replace the faulty actuator.

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