Update on intermittent AC cooling. I finally got my hands on the car again to do some troubleshooting. When it's working the air is cold so I'm not sure how it could be a low refrigerant problem. When AC is blowing hot air the condensor fan is still running but the compressor is not turning. So, something is causing the compressor to not run when it should. From my research on this it seems the fact that the compressor is not running when the condensor fan is running should rule out a problem with the AC switch. I think, but am not certain that it should also rule out a thermostat (in evaporator) problem. I'm not sure if it rules out a possible pressure switch problem. Does anyone know if the condensor fan should run when the the compressor is off due to a pressure problem? Also will a low pressure (like low refrigerant) reading cause the compressor not to run just like a too high pressure? I'm leaning toward a bad compressor clutch relay being the problem. Do those fail intermittently, as opposed to solid failure? Thanks.