My air conditoning in my car has been giving me problems, the magnetic clutch stops and hot air blows instead of cool belt still running, and sometimes the magnetic clutch engages and blows cooler air, so far I have a
had a mechanic put freon in the system, as well as add oil to compresser

Could it be the high compresser switch, is the compressser on it's way out..Also it makes a grinding noise when it engages.. any thoughts?