Air Conditioning Mercury Mountaineer II

Air Conditioning

The A/C refrigerant system is a clutch cycling orifice tube type. The system components are

1. A/C compressor (19703).
2. A/C condenser core (19712).
3. A/C evaporator core (part of 19850 assembly).
4. suction accumulator (19C836).
5. connecting refrigerant lines.

The refrigeration system operation is controlled by the

1. evaporator core orifice tube (19D990).
2. A/C cycling switch (19E561).
3. A/C compressor pressure relief valve (19D644).
4. A/C high pressure cutoff switch (19D594).

The refrigerant system incorporates an A/C compressor controlled by the powertrain control module (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 (19835) 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

1. The climate control assembly is set to a mode which provides an A/C request to the PCM.
2. The A/C cycling switch is reading an acceptable evaporator core pressure.
3. The A/C high pressure cutoff switch is not open due to excessive pressure in the high side of the refrigerant system.
4. The A/C compressor relay is switched to the closed position by the PCM.
5. The engine coolant temperature is not excessively high.
6. The PCM has not detected a wide open throttle (WOT) condition.

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.