Crown Victoria V8-281 4.6L SFI (1998)
Refrigerant Pressure Sensor / Switch: Description and Operation
A/C Pressure Cutoff Switch
An A/C pressure cut-off switch:
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is used on all vehicles to interrupt A/C compressor operation in the event of high system discharge pressures.
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is located on the A/C manifold and tube between the A/C compressor and A/C condenser core.
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is sensitive to discharge pressure.
DUAL FUNCTION
The A/C pressure cut-off switch has the following characteristics:
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The A/C pressure cut-off switch has two sets of contacts. One electrical contact is normally closed.
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When compressor head pressure rises to 2680-3068 kPa (415-445 psi), the contacts open and the compressor operation is shut off.
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When head pressure drops to 1517-1930 kPa (220-280 psi), the contacts again close and allow operation of the A/C compressor.
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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.
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When discharge line pressure reaches 1965-2172 kPa (285-315 psi), these contacts close and engage the high speed fan control.
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When pressure drops to approximately 1724 kPa (250 psi), the contacts again open and the high speed fan control is disengaged.
