Ford Mustang (1999-2004) Service Manual: Dual-Function Pressure Switch (4.6L)

Dual-Function Pressure Switch (4.6L)

The dual-function pressure switch 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 A/C manifold and tube.
  • It is not necessary to discharge the refrigerant system to remove the dual-function pressure switch.
  • A valve depressor, located inside the threaded end of the dual-function pressure switch, presses on the Schrader valve stem.
  • This allows the dual-function pressure switch to monitor the compressor discharge pressure.
  • When the compressor discharge pressure rises, the switch contacts open, disengaging the A/C compressor. When the pressure drops, the contacts close to allow operation of the A/C compressor. For specifications regarding operating pressure(s), refer to Section.

The dual-function pressure switch has a second set of electrical contacts used for high-speed cooling fan control.

When the compressor discharge pressure rises, the contacts close and engage the high speed fan control. When the pressure drops, the contacts open and the high speed fan control is disengaged.

Refrigerant Containment Switch (3.8L)

The refrigerant containment switch is used to interrupt A/C compressor operation in the event of high system discharge pressures.

  • The refrigerant containment switch is mounted on a Schrader-type valve fitting on the high pressure side of the compressor manifold and tube assembly.
  • A valve depressor, located inside the threaded end of the refrigerant containment switch, presses on the Schrader valve stem.
  • This allows the refrigerant containment switch to monitor the A/C compressor discharge pressure.
  • When the A/C compressor discharge pressure rises, the switch contacts open, disengaging the A/C compressor. When the pressure drops, the contacts close to allow operation of the A/C compressor. For additional information regarding operating pressure(s), refer to Section.
  • It is not necessary to discharge the refrigerant system to remove the refrigerant containment switch.
    Suction Accumulator
      NOTE: Installation of a new suction accumulator is not required when repairing the air conditioning system except when there is physical evidence of contamination from a failed A/C compres ...

    Spring Lock Coupling
      The spring lock coupling is a refrigerant line coupling held together by a garter spring inside a circular cage. When the coupling is connected together, the flared end of the female f ...

    Other materials:

    Gauges And Warning Devices
    Refer to Wiring Diagrams Cell 59 , Generic Electronic Module for schematic and connector information. Refer to Wiring Diagrams Cell 60 , Instrument Cluster for schematic and connector information. Refer to Wiring Diagrams Cell 66 , Warning Chime ...

    Changing a fuse
    Fuses WARNING: Always replace a fuse with one that has the specified amperage rating. Using a fuse with a higher amperage rating can cause severe wire damage and could start a fire. If electrical components in your vehicle are not working, a fuse may have blo ...

    Four Wheel Anti-Lock Brake System (4WABS) Hydraulic Control Unit (HCU)
    NOTE: This procedure only needs to be performed if the 4-wheel anti-lock brake (4WABS) hydraulic control unit (HCU) has been installed new or if the HCU lines have been opened. 1. Clean all dirt from and remove the brake master cylinder filler cap ...