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 am working on 2006 Saab 9-7x 5.3, Auto HVAC controls, bucket seats with the floor mounted console. And the part number was given to me from two different dealers, ACDelco 15-73596 Heater and A/C Mode Door Actuator or #89018675 is the GM number. Thanks!
Dan
I need to know the year, make and model of your truck? Do you have auto or manual a/c controls? Do you have a factory floor mounted center console with bucket seats? What was the part number of the installed actuator?
Sparky,
You are the man, the installation instructions and pics of the actual install areas are great, best I found on the web. My issue was no air was coming from the dash vents, only the floor and defrost. I replaced the mode actuator with no problems, easier than I thought and I used an AC/Delco unit to be sure of the fit. I then reset the system and let the vents do their little dance and now I have air coming from the dash vents, great!
BUT, now there is no air coming fro the floor vents, I can’t even make them work when I switch modes. Air only comes out of the dash vents and or the defrost when I want but very little air from the floor vents. I tried the reset procedure to the T and still no luck. Did I do something wrong when installing the actuator? Can I fix this issue?
Thanks in advance!
Dan in Denver
Disconnecting battery power for about one minute clears the HVAC memory and starts the recalibration procedure.
Allowing the vehicle to run for one to four minutes is the time needed for the HVAC system to cycle all of the actuators one at a time. One minute will suffice for a properly working system after 2002. The four minute limit is used for older systems and systems that have issues. The system will try to recalibrate each actuator several times before it sets a code and moves onto the next actuator. Basically after you hear, see or feel each one of the four actuators move full cycle it is time to move onto the next step. The system is looking for the correct feedback from the actuators to determine if the actuators are in sync with the system. If the controls are touched during this process the reclaibration stops and the actuators stay where they were when the interruption occurred.
Waiting 10 seconds after key off command is a signal the system needs before seeing the key on signal that completes the recalibration. Waiting more than thirty seconds will abort the final step of the recailbration and it will fail.
Keep in mind that a recalibration does not guarantee success. Of an actuator is faulty the recalibration will not be completed and a trouble code will be stored. A scan tool that can read HVAC codes and data is needed to further trouble shoot the system. Obviously if a specific actuator is not functioning properly one can make a very good educated guess that the specific actuator is at fault.
I always try to mention light corrosion at the junction block behind the passenger side dash end cap. Simply unplugging and reconnecting the harness connectors several times may clear up a fault. Be sure to pull and push the connectors squarely so that the terminals are not damaged. If the problem returns after a couple of times of trying this the connector is likely not the problem. You will need to test further or replace the affected actuator.
I’d like to know if some of these time frames are critical and why. What exactly is going on during the 1-4 minute wait? Is the 4 minutes just a guideline for around how long it should take? Also, what is happening during the 10-30 second time frame and what happens after 30 seconds if the vehicle is still running?