Durango 2WD V8-5.7L VIN 2 (2007)
Refrigerant Pressure Sensor / Switch: Description and Operation
Operation
OPERATION
The A/C pressure transducer monitors the pressures in the high side of the refrigerant system through its connection to a fitting on the discharge line. The
A/C pressure transducer will change its internal resistance in response to the pressures it monitors. A Schrader-type valve in the discharge line fitting
permits the A/C pressure transducer to be removed or installed without disturbing the refrigerant in the A/C system.
The front control module (FCM) provides a five volt reference signal to the A/C pressure transducer, then monitors the output voltage of the A/C
pressure transducer on a sensor return circuit to determine refrigerant pressure. The FCM broadcasts a refrigerant pressure message to the PCM, which is
programmed to respond to the A/C pressure transducer and other sensor inputs by controlling the operation of the A/C compressor clutch and the
radiator cooling fan to help optimize A/C system performance and to protect the system components from damage. The PCM will disengage the A/C
compressor clutch when high side pressure rises above 3275 kPa (475 psi) and re-engage the clutch when high side pressure drops below 1999 kPa
(290 psi). The A/C pressure transducer will also disengage the A/C compressor clutch if the high side pressure drops below 193 kPa (28 psi) and will
re-engage the clutch when the high side pressure rises above 234 kPa (34 psi). If the refrigerant pressure rises above 1655 kPa (240 psi), the PCM will
actuate the cooling fan. The A/C pressure transducer message to the PCM will also prevent the A/C compressor clutch from engaging when ambient
temperatures are below about 4.5° C (40° F) due to the pressure/temperature relationship of the refrigerant. Refer to the Electric A/C Condenser
Cooling Fan Switch Point chart for condenser cooling fan on/off pressures.
The A/C pressure transducer is diagnosed using a scan tool.
The A/C pressure transducer cannot be adjusted or repaired and must be replaced if found inoperative or damaged.
