Before performing diagnosis of the dual function high pressure switch, or the high pressure cut-off switch, verify that the refrigerant system has the correct refrigerant charge. See Refrigerant System Charge in the Service Procedures section of this group for more information.
For circuit descriptions and diagrams, refer to 8W-42 - Air Conditioning/Heater in Group 8W - Wiring Diagrams.
(1) Disconnect and isolate the battery negative cable.
(2) Unplug the high pressure switch wire harness connector from the switch on the refrigerant system fitting.
(3) On the dual function high pressure switch, check for continuity between terminals C and D. On the two terminal switch, check for continuity between both terminals of the high pressure cut-off 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.