Viper SRT-10 V10-84L (2008) A/C Low Pressure Switch Details
Refrigerant Pressure Sensor / Switch: Description and Operation
A/C Low Pressure Switch
Description
DESCRIPTION
The A/C low pressure switch (1) is a single pole, single throw, pressure actuated switch that is used to control evaporator freeze up.
The A/C low pressure switch is mounted on a fitting located on the top of the A/C accumulator. The A/C low pressure switch fitting on the accumulator
is equipped with an O-ring and contains a Schrader-type valve, which allows the switch to be serviced without discharging the refrigerant system.
Operation
OPERATION
The A/C low pressure switch monitors the pressure of the refrigerant leaving the accumulator to the A/C compressor. The A/C low pressure switch is
electrically connected between ground and the powertrain control module (PCM). The A/C low pressure switch contact opens or closes the path the
ground, signaling the PCM to turn the A/C compressor clutch on and off. This regulates the refrigerant system pressure and controls evaporator coil
temperature. Controlling the evaporator temperature prevents condensate water on the evaporator fins from freezing and obstructing A/C system air flow.
The A/C low pressure switch contacts open when the suction pressure is approximately 131 to 141 kPa (19 to 21 psi) or lower. The switch contacts close
when the suction pressure rises to approximately 241 to 269 kPa (35 to 39 psi) or above. Lower ambient temperatures, below approximately -1° C (30°
F), will also cause the switch contacts to open. This is due to the pressure/temperature relationship of the refrigerant in the system.
The A/C low pressure switch is factory-calibrated and cannot be adjusted or repaired and must be replaced if inoperative or damaged.
