Hi All, since I have no idea how my a/c system works I thought I would ask this question. On my 99 Explorer, how do I know if my a/c is stuck on. With the switch in the blend (feet and vent) position and the temp **** turned to the cool side I am getting a/c out of the vents. With the switch in off my gas milage improves. On the switch blend is to the right of off and the a/c and a/c max are on the left of off. The truck is not hard to start so I don't think the compressor is on all the time (otherwise I would burn out my starter, right?). How is the a/c system supposed to work? Thanks for any help.

 

The Haynes manual will explain how it works and how to check it. HowStuffWorks probably has some good animated diagrams, too.

 

That's the way Ford made them - and the A/C is still on in the VENT/FLOOR position even if you turn the heat up. Yep, that's to cool off all us older folks feet!
That's how it is on my '99 SD anyway - factory installed

 

The a/c clutch engages in all positions except for OFF, Vent, and Floor.

 

Thanks for the info guys.