Dual-Function Pressure Switch

DUAL-FUNCTION PRESSURE SWITCH

The dual-function pressure switch includes 2 separate sets of contacts that are opened at 2 different pressures.

The first set of contacts in the dual-function pressure switch is used to interrupt A/C compressor operation in the event of excessively high discharge pressure in the high-pressure side of the refrigerant system. The PCM monitors the first set of contacts in the dual-function pressure switch (and A/C cycling switch) through the ACCS circuit. When the ACCS circuit is open, the PCM will disengage the A/C compressor clutch.

The second set of contacts in the dual-function pressure switch is used by the PCM to engage the high speed cooling fan. The PCM monitors the second set of contacts through the A/C pressure (ACP) circuit. When the A/C pressure rises above a preset level, the second set of contacts will close and the high-speed cooling fan will be engaged.

The dual-function pressure switch is located on a Schrader-type valve fitting on the compressor-to-condenser discharge line. It is not necessary to recover the refrigerant to remove the dual-function pressure switch.