First noticed AC quit working, the AC light on the control panel does not come on. Then noticed it would not change temp at all, just full on warm, then noticed it will not switch from floor to defrost. Actually it was all at the same time, that's just how I noticed it.
Fan will go from off to high and all stops in between, lights on panel work.
I pulled the easy parts of the dash apart, saw the door behind the glovebox did appear intact as do the mod 1 and 2 doors. The door closest to driver is in the up position, so if it was broke it should have come down, correct?
Checked all the fuses, appear fine.
I changed out the control panel, no change, still have fan only.
Am I missing a fuse somewhere? Something else? Don't want to pull the dash apart if I don't have to, or pay the shop to do it.
Edit to add: I just turned on the fan and switched the temp and heat/defrost selectors while watching and feeling the motors that move the doors, nothing. So I'm pretty sure it's some electrical bug somewhere. Oh joy, an electric gremlin.
Thanks, Bill

 

What year?

 

2006
I spoke with two different service departments, both agreed it must be the control head. So I bought one from parts geek since they had one and it cost 150. The dealer cant get one for at least two or more weeks and it cost double. Installed the new control head and same thing.
Fuses are good, it checked for power to the control head and found 12V coming in. I'm at a loss. Could be a faulty knock off control unit so I ordered one from the dealer and will try that when it arrives. Of course that's after my big road trip coming up next week.

 

Get a service manual for your truck. See how the system is supposed to work, then find out what part ISN'T doing its job.