B3000 SE Regular Cab 4WD V6-3.0L OHV (1998)
Air Conditioning Switch: Description and Operation
The A/C cycling switch is mounted on a Schrader valve-type fitting on the top of the receiver/drier.
- A valve depressor, located inside the threaded end of the A/C cycling switch, presses in on the Schrader valve stem.
- This allows the suction pressure inside the receiver/ drier to control the operation of the A/C cycling switch.
- The electrical switch contacts open when the suction pressure drops to 152 - 193 kPa (22 - 28 psi).
- The contacts close when the suction pressure rises to 276 - 324 kPa (40 - 47 psi)
- When the A/C cycling switch contacts close, the signal to energize the A/C clutch is sent to the wide open throttle A/C cutoff relay.
- When the A/C cycling switch contacts open, the A/C clutch field coil is deenergized and compressor operation stops.
- The A/C cycling switch will control the A/C evaporator core pressure at a point where the plate/fin surface temperature will be maintained slightly
above freezing.
- This prevents icing of the A/C evaporator core and blockage of airflow.
- It is not necessary to discharge the refrigerant system to remove the A/C cycling switch.
