F 150 2WD V8-5.4L Flex Fuel (2008)
Refrigerant Pressure Sensor / Switch: Description and Operation
A/C Cycling Switch
A/C CYCLING SWITCH
The A/C cycling switch is mounted on a Schrader valve-type fitting on the suction accumulator.
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A valve depressor, located inside the threaded end of the A/C cycling switch, presses in on the Schrader valve stem.
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This allows the suction pressure to control the operation of the A/C cycling switch.
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Battery voltage is present at one side of the A/C cycling switch at all times when the ignition switch is in the RUN position.
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When the switch contacts are closed, the battery voltage circuit is completed to the PCM to signal that the low-side refrigerant system pressure is
acceptable for A/C compressor operation.
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When the switch contacts are open, the battery voltage circuit is opened to signal the PCM that the low-side refrigerant system pressure is too low
for A/C compressor operation.
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The A/C cycling switch will control the evaporator core pressure at a point where the plate/fin surface temperature will be maintained slightly
above freezing.
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This prevents icing of the evaporator core and blockage of airflow.
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It is not necessary to recover the refrigerant to remove the A/C cycling switch.