Grand Cherokee 2WD V8-5.2L VIN Y (1998)
Low Pressure Sensor / Switch: Description and Operation
Low Pressure Cycling Clutch Switch
The low pressure cycling clutch switch is located on the top of the accumulator. The switch is screwed onto an accumulator fitting that contains a
Schrader type valve, which allows the switch to be serviced without discharging the refrigerant system. The accumulator fitting is equipped with an
0-ring to seal the switch connection.
The low pressure cycling clutch switch is connected in series electrically with the high pressure cut-off switch, between ground and the Powertrain
Control Module (PCM). The switch contacts open and close causing the PCM to turn the compressor clutch on and off. This regulates the
refrigerant system pressure and controls evaporator temperature. Controlling the evaporator temperature prevents condensate water on the
evaporator fins from freezing and obstructing air conditioning system air flow.
The low pressure cycling clutch switch contacts are open when the suction pressure is approximately 141 kPa (20.5 psi) or lower. The switch
contacts will close when the suction pressure rises to approximately 234 to 262 kPa (34 to 38 psi) or above. Lower ambient temperatures, below
approximately -1 degree Celsius (30 degree Fahrenheit), will also cause the switch contacts to open. This is due to the pressure temperature
relationship of the refrigerant in the system.
The low pressure cycling clutch switch is a factory-calibrated unit. It cannot be adjusted or repaired and, if faulty or damaged, it must be replaced.
