When I fire up my XJ, I have A/C no matter where I slide the ****. If I try to get defrost, vent, heat, or even turn slide all the way left to "OFF", nothing changes. I can change the speed of the fan and slide from hot to cold but it always comes out the front vents and A/C compressor runs all the time. When I shut the truck off, the blower motor goes off. I have vacuum to the little door under the glove box whenever the vehicle is running.

Any clue on how to fix it or what might be wrong?