High Pressure Sensor / Switch: Description and Operation

Location
In the line from the compressor to the condenser.

Function
Protection of the air conditioning system against a pressure overload by cutting out the compressor.

Operation
The function of the high pressure switch is to protect the high pressure section of the refrigerant circuit. When pressure exceeds the maximum value of 2965 kPa (430 psi) because, for instance, the air flow through the condenser is impeded or the high-pressure line is blocked, the high pressure switch switches the compressor off.

Only when the pressure has fallen once more to 2241 kPa (325 psi) bar is the compressor switched on again. At a pressure level of 2241 kPa (325 psi) the PCM switches to high fan speed.

Only when the pressure has fallen once more to 1717 kPa (249 psi) does the PCM switch to low fan speed.