Dual Function Pressure Switch - 6.0L Diesel
WARNING: This page is about a different car, the 2004 Ford Pickup, 2004 Ford F550 Super Duty, 2004 Ford F450 Super Duty, 2004 Ford Excursion, and 2004 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
The dual function pressure switch (DFPS) is used to interrupt A/C compressor operation in the event of high system discharge pressures.
- The dual function pressure switch is mounted on a Schrader valve-type fitting on the high pressure side of the compressor manifold and tube assembly.
- A valve depressor, located inside the threaded end of the DFPS, presses on the Schrader valve stem.
- This allows the DFPS to monitor the compressor discharge pressure.
- The DFPS has two sets of electrical contacts. One set of contacts is normally closed and is used for A/C high pressure cutoff.
- When the A/C compressor discharge pressure rises, the switch contacts open, disengaging the A/C compressor. When the compressor discharge pressure drops, the switch contacts return to the closed position, and A/C compressor operation resumes. For specifications regarding operating pressures, refer to CLIMATE CONTROL SYSTEM - GENERAL INFORMATION .
- The second set of electrical contacts in the DFPS is used for engine cooling fan control.
- It is not necessary to recover the refrigerant to remove the DFPS.