A/C Pressure Sensor/Switch - Cooling Fan: Description and Operation

The A/C pressure fan switch is a normally closed switch that monitors high side pressure during A/C operation. When high side pressure reaches 1448 kPa (210 ± psi) the switch opens signaling the PCM to turn the primary cooling fan to high speed. The switch closes once high side pressure drops to approximately 1103 kPa (160 psi).