Refrigerant Pressure Sensor / Switch: Description and Operation
A/C TRIPLE PRESSURE SWITCHThe A/C triple pressure switch consists of a High-Low pressure switch (A/C pressure switch A) and a Middle pressure switch (A/C pressure switch B).
A/C Triple Pressure Switch:
High-Low pressure switch
If the refrigerant pressure becomes too high (due to blockage), or too low (due to leakage), the A/C triple pressure switch sends a signal to the fan control unit to prevent the compressor from operating.
A/C Triple Pressure Switch:
Middle pressure switch
If the refrigerant pressure goes above or below 1,550 kPa (15.5 kgf/sq.cm, 220 psi), the A/C triple pressure switch sends a signal to the ECM, then the ECM operates the idle control.