its a common problem... there are 3 little slits in the dash under your radio... there is an in-car temp sensor. its usually covered in dust and other things the little fan in there sucks up. blow it out with some compressed air and it should start working. id suggest using canned air or if you have an air compressor turn the pressure way down and blow it out with an air chuck.Our A/C is not blowing cool. It started today blowing just hot air. The fan blows at all speeds. Could just adding coolant help, I am sure that there is a leak for it to start blowing hot air.
What are some things to self diagnose?