Air Conditioning: Notes
WARNING: This page is about a different car, the 2009 Mercury Mountaineer, 2009 Ford Explorer Sport Trac, and 2009 Ford Explorer. However, it is still accessible from the selected car via links, so may be relevant.
The A/C system is a clutch cycling orifice tube type. The system components include the following:
- A/C compressor
- A/C condenser core
- A/C evaporator core
- Suction accumulator
- Connecting refrigerant lines
The A/C system operation is controlled by the following:
- Evaporator core orifice tube
- A/C cycling switch
- A/C compressor pressure relief valve
- A/C pressure transducer
The A/C system incorporates an A/C compressor controlled by the PCM through an A/C clutch relay.
The A/C cycling switch senses evaporator core pressure to control A/C compressor operation.
An evaporator core orifice tube is installed in the condenser-to-evaporator line to meter the liquid refrigerant into the evaporator core.
The A/C compressor clutch will only be engaged by the PCM if all of the following conditions are met:
- The climate control assembly or HVAC module is set to a mode which provides an A/C request to the PCM.
- The A/C cycling switch is reading an acceptable evaporator core pressure.
- The A/C pressure transducer is reading an acceptable pressure in the high side of the refrigerant system.
- The A/C compressor relay is switched to the closed position by the PCM.
- The engine coolant temperature is not excessively high.
- The PCM has not detected a wide open throttle (WOT) condition.
An A/C compressor pressure relief valve is installed in the compressor to protect the refrigerant system against excessively high refrigerant pressures.