Temperature Control

Temperature Control

The temperature control switch relays operator input to the air conditioning unit, to control A/C system temperature output. The switch (C0275) receives an ignition feed from fuse 15 of the passenger compartment fuse box (C0580) on a WG wire.

When the switch is turned to position 1, a feed is provided to the air conditioning unit (C1273) on a UY wire. When the switch is turned to position 2, a feed is provided to the air conditioning unit (C1273) on a RW wire. When the switch is turned to position 3 (maximum cooling), a feed is provided to the air conditioning unit (C1273) on a B wire.

The switch (C1273) is earthed on a UB then B wire.

Evaporator Temperature Sensor

The evaporator temperature sensor is used to ensure the evaporator doesn't freeze. The air conditioning unit (C1273) provides a feed to the temperature sensor (C0134) on a K wire, and receives a return signal on a UW wire. The air conditioning unit (C1273) is earthed on a UB then B wire.

Compressor Clutch

When A/C is requested, the compressor clutch switch contacts (C0847) close. This allows current to flow from the compressor clutch relay coil (C1268) to the pressure sensor (C0279) on a WK then BS wire.

The air conditioning unit (C1273) provides a feed to the other side of the pressure sensor (C0279) on a UG wire. If the pressure within the high pressure side of the A/C system is within operational limits, the air conditioning unit removes its feed and replaces it with a path to earth. This has the effect of energising the compressor clutch relay.

The energised compressor clutch relay (C1268) provides a feed to the compressor clutch (C0182) on a BG wire. The clutch (C0182) is earthed on a B wire.

Condenser Fan

The cooling fan relay coil (C0019) receives a feed from fuse 15 of the passenger compartment fuse box (C0580) on a WG wire. The earth path for the relay coil (C0019) is controlled by the air conditioning fan switch (C0848) on a BP wire. If condenser cooling is required, the switch contacts close, creating a path to earth on a B wire.

The energised cooling fan relay (C0019) is now able to provide a feed to the condenser fan motor (C0280) on a BN wire. The motor (C0280) is earthed on a B wire.