Was reading through some of the hvac questions for Chevy trucks and have seen similar answers about newer trucks but not for an 02. I have a 02 3/4 ton avalanche 4wd and believe the blend motor on the drivers side is bad or needs calibration. Does not change from dash vents to floor or defrost. On other vehicles a recalibration is done by pulling a 10amp fuse I believe but I do not see this fuse in my box. Ac controls are knob style with 3 knobs but it does have an auto setting with degrees of temperatures. I recently purchased vehicle and the man I bought it from had a new blend motor he never installed. I removed old one and plugged new motor in. When I turned the truck on the first time the motor moved one direction but no other movement when I change vent settings. I was trying to find out if there is a reset procedure that is different on this type of controls or maybe something else is wrong. Also the motor the guy had purchased already does not have the plastic cam attached the engages the gear on ac box , motor looks like the one advertised online for the passenger side but others say they are the same motor and I figured maybe I can swap the cam from existing motor to new motor. So are motors the same on passenger and driver side and is there a reset procedure for these different controls. Please let me know if you can help or have any ideas. Thanks

ID Status Date Year Make Model Transmission Type A/C Controls Public/Private
#14146 Closed 2002 Chevrolet Avalanche public

Ac blend motor question for 02 3/4 ton avalanche


The mode actuator is not the same as any other actuator on your Avalanche. Here is a link to the correct part for comparison. ACDelco part number 15-72505

Actuator Recalibration according to GM Service Information with some additional information from Sparky highlighted in bold font.

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:

    1. Turn OFF the ignition.
    2. Remove the battery positive voltage circuit fuse (the radio fuse in the underhood fuse box) 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.

  1. Wait 60 seconds.
  2. Install the fuse.
  3. Turn ON the ignition for at least 60 seconds.
  4. Do not touch anything. 
  5. Turn the ignition off for at least 10 seconds but no more than 30 seconds. 
  6. Turn the ignition on and check the system operation. 
  7. Wait 60 seconds before installing a scan tool.

Thanks for the tips. Would you know what voltages would be on plug for pin testing or any other ways to test controls.


I have been looking through GM testing procedures and all I have found require use of a scan tool. I have included a wiring diagram to show the actuator controls. The power, ground and sensor wiring is pretty clear cut but I have not been able to find out what voltage is used on the white control wire. My assumption is that it should be similar to later models.  -2.5, 0 and +2.5 volts

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