Pressure Transducer
WARNING: This page is about a different car, the 2004 Mercury Monterey and 2004 Ford Freestar. However, it is still accessible from the selected car via links, so may be relevant.
The pressure transducer is used to interrupt A/C compressor operation in the event of high system discharge pressures.
- The A/C Pressure Transducer is used by the PCM to monitor A/C refrigerant high side pressures. A 5 volt reference voltage, ground and feedback circuit is provided by the PCM to the A/C Pressure Transducer. Feedback voltage will vary in correlation to A/C refrigerant high side pressures.
- The pressure transducer 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 pressure transducer, presses on the Schrader valve stem.
- This allows the pressure transducer to monitor the A/C compressor discharge pressure.
- If A/C refrigerant high side pressures reach a predetermined pressure, the PCM will enable engine cooling fan high speed operation. If pressures continue to rise, the PCM will disable A/C compressor operation via the A/C relay. Once A/C refrigerant high side pressures fall below the predetermined level, the PCM will enable the A/C compressor, (if all other A/C compressor inputs are within range, i.e. PSP, ECT, etc).
- It is not necessary to recover the refrigerant system to remove the pressure transducer.