High Pressure Sensor / Switch: Testing and Inspection

Fig. 1 Testing A/C high pressure switch:

1. Disconnect high pressure switch connector.
2. Install manifold gauge set to A/C system.
3. Using an ohmmeter, measure continuity between terminals 2 and 3 of A/C high pressure switch. When A/C system high side pressure is below 178 psi, there should be continuity, and when high side pressure is 220 psi or higher, there should be no continuity, Fig. 1.
4. Remove manifold gauge set and reconnect high pressure switch connector.