High Pressure Sensor / Switch: Testing and Inspection

Fig 25 High Pressure Cut-off Switch -- Typical:

HIGH PRESSURE CUT-OFF SWITCH
1. Verify that the refrigerant system is properly charged.
2. Unplug the high pressure switch wire harness connector and test for continuity between the switch terminals. There should be continuity If OK, refer to the wiring diagrams and repair the circuits as required. If not OK, replace the faulty switch.

Fig 35 Low Pressure Cycling Clutch Switch Removal/Installation:

NOTES:
- Before performing diagnosis of the low pressure cycling clutch switch, be certain that the switch is properly installed on the accumulator fitting. The low pressure cycling clutch switch should be hand-tightened onto the fitting. If the switch is too loose it may not open the Schrader-type valve in the accumulator fitting, which will prevent the switch from correctly monitoring the refrigerant system pressure.
- Verify that the refrigerant system has the correct refrigerant charge.

LOW PRESSURE CYCLING CLUTCH SWITCH
1. Unplug the low pressure cycling clutch switch wire harness connector from the switch on the accumulator, and install a jumper wire between the two connector cavities.
2. Connect a manifold gauge set to the refrigerant system service ports.
3. Place the heater-A/C mode control switch knob in any A/C position and start the engine.
4. Check the continuity between the two terminals of the low pressure switch. There should be continuity with a suction pressure reading of 296 kPa (43 psi) or above, and no continuity with a suction pressure reading of 172 kPa (25 psi) or below. If OK, test and repair the compressor clutch control circuit as required. If not OK, replace the faulty switch.