This morning when I turned on the climate control, it blinked on and off a few times and now, the only way I get any heat is to turn it up to 90 degrees. 85 and below I get A/C ? I've also lost fan and temp control on the steering wheel. I can change fan speed at the head itself, I can also change the temp setpoint at the head too but it dosen't do any good. Checked fuses and they are good. Also tried searching around for loose wiring but I'm thinking maybe the thermostat has went out and clicking it to 90 degrees is a built in fail safe for heat ? It's a 05 Lariat 4x4.

 

Sounds like the EATC control unit went out.

They are someone costly, don't know if you want to mess with a bone yard on this.