Wtih Manual A/C Heater

An A/C pressure cut-off switch is used on all vehicles to interrupt operation of the A/C compressor in event of high-system discharge pressures.

The A/C pressure cut-off switch is located in the A/C compressor to condenser discharge line between the A/C compressor and the A/C condenser core.

Dual
The A/C pressure cut-off switch has two sets of contacts. One electrical contact is normally closed.
^ When compressor head pressure rises to approximately 2896 kPa (420 psi), the contacts open and the compressor operation is shut off.
^ When head pressure drops to approximately 1724 kPa (250 psi), the contacts again close and allow operation of the A/C compressor.
^ Shutting down compressor operation prior to the pressure relief valve set point of 3103 kPa (450 psi) makes sure refrigerant is contained in the A/C system.

The switch contains a second set of electrical contacts for the engine cooling fan motor which are normally open.
^ When discharge line pressure reaches approximately 2241 kPa (325 psi), these contacts close and engage the engine cooling fan motor.
^ When pressure drops to approximately 1896 kPa (275 psi), the contacts again open and the engine cooling fan motor is disengaged.