Temp Control Not Working

[Bighatnocattle]

2003 GMC Yukon XL. Was warm here today and used the AC - which I haven't had to use in a month or so. When turning on the AC - I'm not getting cold air on the driver side. I have dual zone temp controls on this vehicle. Pass side is working fine. Lots of cold air coming out passenger side. I've got both temp settings at 60. What's up?? I tried it with manual and automatic air with same results. Thanks.

[GM-Tech]

The HVAC system saw something it didn't like in the position of the left temperature door. When that happens, it forces the door to the default position, which is the heat position.

 

*Sometimes* this can occur after a battery disconnect and sometimes a battery disconnect will also correct it. That's because that forces the HVAC system to relearn the door positions and if the left door then passes the test, it will work as it should.

 

We have a function on our Tech 2 scanner to do a HVAC actuator recalibration and this will often fix it too. If there's a real fault in the actuator, no amount of relearning the door positions will help and you'll need a new actuator.

[Bighatnocattle]

Thanks for the reply, I appreciate it. So I should disconnect the battery – right? Any other suggestions?