Air Conditioning: Notes

WARNING: This page is about a different car, the 2005 Lincoln LS. However, it is still accessible from the selected car via links, so may be relevant.

The A/C refrigerant system is a clutch cycling, thermostatic expansion valve type. The system components are:

A/C compressor
A/C clutch and clutch field coil
A/C condenser core
A/C evaporator core
Thermostatic expansion valve (TXV)
Receiver/drier
Connecting refrigerant lines
The refrigeration system operation is controlled by the:
TXV.
evaporator discharge air temperature sensor.
A/C compressor pressure relief valve.
A/C pressure transducer.
powertrain control module (PCM).
dual-zone EATC module.
ambient temperature sensor.

The refrigerant system incorporates a variable capacity A/C compressor. The A/C compressor clutch engagement is controlled by the vehicle PCM.

The evaporator discharge air temperature sensor senses evaporator discharge air temperature. The dual-zone EATC module monitors the evaporator discharge air temperature sensor and communicates with the PCM to control clutch cycling. The dual-zone EATC also monitors the ambient air temperature sensor and disables A/C operation when the ambient air temperature is below 0°C (32°F).

The A/C pressure transducer is located in the compressor discharge line and is monitored by the PCM. If high or low refrigerant pressures are experienced, the PCM will interrupt A/C compressor operation.

The pressure relief valve is installed in the compressor manifold and tube assembly and protects the system from excessively high refrigerant pressure.

The TXV, which is mounted to the evaporator core inlet and outlet tubes, contains an adjustable orifice which provides the restriction that separates the high and low-pressure liquid phases in the refrigeration system.