Check your owner's manual for fuses related to a/c and check them. If you are facing the car, there is a canister to the right of the radiator, and a wire plus in there, and there is a switch under the coolant tank on the passenger side fender, see if those are connected. If you put it into Defrost mode does the a/c compressor come on? If so the swich in the dash could be bad. Many possibilities.