I just had my stereo stolen and had to replace the following damaged or stolen components:
-stereo/climate control bezel
-hazard light switch
-stereo and wiring harness

Before I installed the climate controls into the new bezel, the controls were just floating around in my dash and a couple of the wires in the climate controls wiring harness had come undone. The fans would go on full blast unless I stuck the wires back in, which I had to do frequently.

I got everything back in the dash and thought I fixed the problem with the climate control wires coming out. Everything works fine unless I turn my headlights on, at which point the fans go on full blast. Turn off the headlights and everything works fine again. Obviously there's some sort of short, but does anyone know where I should start looking?

 

Sounds like the wires that were sticking out are gonna be the problem. Go back and make sure they arent touching anything. And make sure everything is connected right.