Air Conditioning: Notes

WARNING: This page is about a different car, the 2004 Lincoln Navigator and 2004 Ford Expedition. However, it is still accessible from the selected car via links, so may be relevant.

The air conditioning system components are.

A/C compressor (19703).
A/C condenser core (19712).
A/C evaporator core.
Receiver/drier (19959).
Connecting refrigerant lines.
Thermostatic expansion valve (19849).
A/C thermostatic switch.
A/C high pressure cutoff switch (19D594).
A/C compressor pressure relief valve (19D644).
Low charge protection switch

The refrigerant system incorporates an A/C compressor controlled by the powertrain control module (PCM) through an A/C clutch relay.

The A/C compressor clutch will only be engaged by the PCM if all of the following conditions are met:

The climate control assembly is set to a mode which provides an A/C request to the PCM.
The A/C thermostatic switch is reading a temperature above 37°F.
The high pressure cutoff switch is not open due to excessive pressure in the high side of the refrigerant system.
The low charge protection switch is not open due to insufficient low side refrigerant system pressure.
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.

For additional information concerning operating specifications, refer to CLIMATE CONTROL SYSTEM-GENERAL INFORMATION .

An A/C compressor pressure relief valve is installed in the compressor manifold and tube assembly (19D734) to protect the refrigerant system against excessively high refrigerant pressures.

Refrigerant flow into the evaporator core is metered by a thermostatic expansion valve.

For additional information concerning the refrigerant cycle and principles of A/C operation, refer to CLIMATE CONTROL SYSTEM-GENERAL INFORMATION .