A/C High Pressure Switch Test

Before performing diagnosis of the a/c high pressure switch, verify that the refrigerant system has the correct refrigerant charge.
1. Disconnect and isolate the battery negative cable.
2. Unplug the a/c high pressure switch wire harness connector from the switch on the refrigerant system fitting.
3. On the four terminal a/c high pressure switch, check for continuity between terminals C and D. On the two terminal a/c high pressure switch, check for continuity between both terminals of the switch. There should be continuity. If OK, test and repair the A/C switch sense circuit as required. If not OK, replace the faulty switch.