Dakota R/T 2WD V8-5.9L VIN Z LDC (1999)
Low Pressure Sensor / Switch: Testing and Inspection
Before performing diagnosis of the low pressure cycling clutch switch, be certain that the switch is properly installed on the accumulator 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. Remember that lower ambient temperatures, below about -1° C (30° F), during cold weather will open the switch contacts
and prevent compressor operation due to the pressure/temperature relationship of the refrigerant.
Also verify that the refrigerant system has the correct refrigerant charge. See Refrigerant System Charge in the Service Procedures for more information.
1. Disconnect and isolate the battery negative cable.
2. Unplug the low pressure cycling clutch switch wire harness connector from the switch on the accumulator fitting.
3. Install a jumper wire between the two cavities of the low pressure cycling clutch switch wire harness connector.
4. Connect a manifold gauge set to the refrigerant system service ports. See Refrigerant System Service Equipment and Refrigerant System Service
Ports in the Description and Operation for more information.
5. Connect the battery negative cable.
6. Place the heater-A/C mode control switch knob in any A/C position and start the engine.
7. Check for continuity between the two terminals of the low pressure cycling clutch switch. There should be continuity with a suction pressure
reading of 262 kPa (38 psi) or above, and no continuity with a suction pressure reading of 141 kPa (20.5 psi) or below. If OK, test and repair the
A/C switch sense circuit as required. If not OK, replace the faulty switch.
