Durango 4WD V8-5.9L VIN Z (1998)
High Pressure Sensor / Switch: Description and Operation
High Pressure Cut-off Switch
The high pressure cut-off switch is located on the discharge line near the compressor. The switch is screwed onto a fitting that contains a
Schrader-type valve, which allows the switch to be serviced without discharging the refrigerant system. The discharge line fitting is equipped with
an O-ring to seal the switch connection.
The high pressure cut-off switch is connected in series electrically with the electronic cycling clutch switch and the low 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 prevents compressor operation when the discharge line pressure approaches high levels.
The high pressure cut-off switch contacts are open when the discharge line pressure rises above about 3100 to 3375 kPa (450 to 490 psi). The
switch contacts will close when the discharge line pressure drops to about 1860 to 2275 kPa (270 to 330 psi).
The high pressure cut-off switch is a factory-calibrated unit. The switch cannot be adjusted or repaired and, if faulty or damaged, it must be
replaced.
