I discovered by accident one way to do a quick fix: unplug both battery wires and touch the 2 contacts together. Reattach and give it a shot...its like a PCM reboot - not good for it I'm sure but discovered it when I cudn't get my TB to operate and I was stuck.
My AC is all wacky too...when it blows steady thru the defrost its an 'override' mode and its either the actuator or a relay gone bad. Mine actually only blows max cold at any temp 89* or lower, unless I set it to 90*, then it blows full hot! ...back to the dealer!!!

 

I thought that there were 3 actuators...one for the mode (face, foot, defrost, etc.), one for temp control, and one for fresh/recirc...I could be wrong though (wouldn't be the first time lol )

 

Just an update....After pulling the fuse and letting the truck warm up, replacing the fuse, and starting the truck it went through a "recalibration" of the climate control doors. I'm sure it does roughly the same as pulling the battery cable, but with less work. While it is doing the "recalibration" you are not supposed to touch the HVAC controls. It's been a couple of months since then and zero issues....except the volt gauge, but a few people helped me out on that already....Glad GM is stepping up to the plate on that recall...

 

Which fuse? HVAC? Do you put the temp sliders in the middle or anything special?

I need to recalibrate mine. I had to get a boost a few weeks ago (dead battery), got a new battery and the A/C has switched to heat a couple times since then.

 

I forget which one....I had to hunt for it in the fuse panels until the display went blank...Mine is a automatic climate control...so it may not work for regular HVAC controls.

 

Mine does not randomly change temps. but the drivers side temp control motor (blender door?) is about at mid point temp to all the way cold it keeps making grinding type noises like it cant find its position. Once in the past it blew the hvac fuse and if I ever disconnect the battery it wont recalibrate on the dirvers side. It'll go to full hot and stay there untill repeted attempts at pulling the fuse and turning car on and off.

also has codes
[HVAC] B0414
[HVAC] B3770

i'm open to suggestions but i'm guessing, "blender motor"?

 

Sounds like a bad actuator, aka, blend door motor...

 

Found some info that might help.

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Alternate Method (w/o Scan Tool)

1. Clear all DTCs.
2. Place the ignition switch to the OFF position.
3. Install the HVAC actuator.
4. Connect all previously disconnected components.
5. Remove the HVAC/ECAS fuse for a minimum of 10 seconds.
6. Install the HVAC/ECAS fuse.
7. Start the vehicle.
8. Wait 40 seconds for the HVAC control module to self-calibrate.
9. Verify that no DTCs have set as current DTCs.

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It needs the passenger side temp. actuator. It's under the dash and kind of a pain in the *** to change.