A/C Pressure Cutoff Switch

An A/C pressure cut-off switch:
- is used on all vehicles to interrupt A/C compressor operation in the event of high system discharge pressures.
- is located on the A/C manifold and tube between the A/C compressor and A/C condenser core.
- is sensitive to discharge pressure.

DUAL FUNCTION
The A/C pressure cut-off switch has the following characteristics:
- The A/C pressure cut-off switch has two sets of contacts. One electrical contact is normally closed.
- When compressor head pressure rises to 2680-3068 kPa (415-445 psi), the contacts open and the compressor operation is shut off.
- When head pressure drops to 1517-1930 kPa (220-280 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) make sure refrigerant is contained in the A/C system.

The switch contains a second set of electrical contacts for high speed fan control which are normally open.
- When discharge line pressure reaches 1965-2172 kPa (285-315 psi), these contacts close and engage the high speed fan control.
- When pressure drops to approximately 1724 kPa (250 psi), the contacts again open and the high speed fan control is disengaged.