The wiring diagram shows that there is a high pressure and low pressure switches. The one near the front cover concealing the evaporator near the drivers side has a temperature probe that will shut off the compressor if the evaporator is too hot or cold. I am trying to find the switches that respond to pressure as I am using an electric compressor as opposed to one that runs off the engine. I did not have room to run the conventional compressor. The ports that you refer to are the pressure ports to see if you are full in terms of system pressures. Those I see, it is the others that are eluding me and the one on the dryer does not shut off the compressor, it turns off the rad fans. Any help you could give me would be appreciated. Thank you.