Operation D series only

Operation D series only

Power is fed from fuse G in the engine compartment fuse box on a W wire to the condenser fan and compressor clutch relays. From the condenser fan relay it is fed on a U/B wire to the condenser fan and, from compressor clutch relay on a R wire to the compressor clutch.

When the A/C is switched ON, if the air temperature in the evaporator is warm enough (above 5°C) the condenser fan relay will be energised and the condenser fan will operate at slow speed. If pressure in the A/C system is normal, the earth signal will be detected by the ECM on the U/R wire. An earth potential will be provided by the ECM to energise the compressor clutch relay to engage the compressure clutch.

The compressor will continue to operate and cold air will be blown into the passenger compartment, until the air temperature measured in the vicinity of the evaporator, falls below 2°C. At this temperature, the thermo switch will open and power will be removed from the fan motor and compressor magnetic clutch relays. When the temperature rises above 5°C again, the thermo switch contacts will close and power to the condenser fan and clutch relays will be restored.

Power will also be removed from the air conditioning system by the ECM, if the engine coolant temperature rises above 120°C. Operation of the air conditioner will be inhibited until the temperature falls to 116°C.

A lamp will light in the A/C switch (when the switch is operated and the blower is enabled), by power fed on a B/U wire from fuse 13 in the passenger compartment fuse box. Background illumination for the switch is provided when the vehicle sidelights are on, by a feed from fuse 19 on an R/B wire. The return path for this lamp is via a B wire.