AC problem

[2010gmcyukon]

Did you re-calibrate the blender door position? My blender door was acting up and was able to re-calibrate via my tech-2 scanner. Unfortunately my AC system still is in protection mode and will not engage my AC compressor.

I did these recalibration steps based on comments on this video. It did reset to 74 degrees, so hopefully that means I did it correctly.

1. Turned on ignition to accessory and set the heating system to AUTO. It does not matter what the temperature settings are when you do this, just that the system is set to automatic. I suggest you do set the temp of the system to any temperature other than 74 degrees as this is the default setting the system goes to during calibration and you can thus confirm the system is calibrating as you will see the setting has changed from what you set to 74 degrees during this process.
   
2. Turned off ignition.
   
3. Removed fuse #39 "HVAC Batt" in the engine compartment fuse block. [There are two other fuses (#48 & #55) that are for the HVAC/IGN that do NOT have to be removed.]
   
4. Leave fuse #39 out for at least one minute.
   
5. Re-insert fuse #39.
   
6. Start the vehicle but DO NOT touch any of the AC-Heater controls. The display of temp should now read 74degrees.Let the car run for 2 minutes without touching any controls.
   
7. Turn off the engine for at least 10 seconds but NOT more than 30 seconds and restart the engine. The system should now be re-calibrated.

 

[Denali Deen]

I HAVE ALSO BEEN HAVING ISSUES WITH MY 2010 DENALI. IT KINDA HAS A MIND OF ITS OWN SOMETIMES IT WILL GET COLD QUICK AND STAY THAT WAY OTHER TIMES IT WILL JUST BLOW COOL TO WARM AIR AND NOT TILL I HAVE BEEN DRIVING AND THE ENGINE IS UNDER LOAD WILL IT START TO COOL OFF AND GET TO THE RIGHT TEMP. THEN WHEN COMING TO A STOP IT WILL WARM BACK UP. I HAVE HAD IT PROFESSIONALLY EVAC'D AND RECHARGED AND THAT MADE NO DIFFERENCE. REPLACED THE COMPRESSOR AND NO REAL DIFFERENCE AND THEN REPLACED THE ORIFICE TUBE. THAT WAS FAIRLY CLOGGED IT SEEMS A LITTLE BETTER BUT WILL STILL RANDOMLY CUT OUT AND STOP BLOWING AS COLD AS IT SHOULD. I AM IN THE SOUTH AND 100 DEGREES AND FULL HUMIDITY IS AN EVERYDAY THING SO I REALLY WOULD LIKE TO FIND THE ISSUE TO MINE AS WELL. COULD A BAD/GOING BAD CONTROL HEAD CAUSE THAT?

 

[2010gmcyukon]

Following up on my post, as I had a shop look at the AC and it is now working. Here are their notes:

Initial inspection of HVAC system found pressure line frozen at orifice tube on evaporator side. Hook machine up and found low pressures on high and low side. Recover R134a from vehicle and found .4 lb in vehicle. System calls for 2.5 lb. Evac and recharge required.
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They also said that they put in some UV dye. The system held vacuum and they did not detect any leaks. Not sure what caused the condition, but I'm glad to have it working again.