Did you try cleaning it out? There are 2 parallel fine wire sensors just above the fan that collect dust and lint which may cause a temporary short.

 

Yeah. Took it out and it had very little dust on it. Cleaned up what was there and reinstalled. Didn't see anything that looked like damage or bad connections or anything. The temp control seemed to work briefly after reinstalling, but then it went back to only engaging the AC when set to LO.

I ordered the Motorcraft sensor. I'll update the thread after it gets here and I get it installed. Here's to hoping.

 

Roger that - good luck and please post back with your results...