Dakota Quad Cab 2WD V8-5.9L VIN Z LDC (2002)
Low Pressure Sensor / Switch: Description and Operation
A/C LOSS OF CHARGE SWITCH
The a/c loss of charge switch is located on the top of the accumulator. The switch is used to measure if refrigerant system pressure goes too low. It
is not responsible for cycling the a/c compressor clutch. 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 O-ring to seal the
switch connection.
The loss of charge switch is connected in series electrically with the Heater-A/C controls 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 system charge is low and prevents damage to the compressor. The switch opens with a pressure of 7 to 13 psi and closes when the
pressure rises to 15 to 25 psi.
