Dual-Function Pressure Switch

Dual-Function Pressure Switch







The dual-function pressure switch is located on the receiver drier and 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 in-series with the low-charge protection switch. When the contacts are 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 installed on a Schrader-type valve core fitting on the receiver/drier. It is not necessary to recover the refrigerant to remove the dual-function pressure switch.

Low-Charge Protection Switch







The low-charge protection switch is installed on the evaporator outlet line to cycle the A/C compressor off in the event of a low refrigerant charge. The PCM monitors the low-charge protection switch in-series with the dual-function pressure switch. When the low-side pressure drops below acceptable levels, the low-charge protection switch contacts open. When the low-charge protection switch contacts are open, the PCM will disengage the A/C compressor clutch.

The low-charge protection switch is installed on a Schrader-type valve core fitting on the evaporator outlet line. It is not necessary to recover the refrigerant to remove the low-charge protection switch.