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 air conditioning unit (C1273) provides a feed to the Engine Control Module (ECM) (C0658) via the pressure switch (C0279) on a UG then BS then YS wire. If the pressure within the high pressure side of the A/C system is within operational limits, the ECM energises the compressor clutch relay.

The compressor clutch relay coil (C0689) receives a feed from the energised main relay (C0063) on an NO wire. To energise the compressor clutch relay the ECM (C0658) provides an earth path for the relay coil (C0689) on a BS wire.

The energised compressor clutch relay (C0689) provides a feed to compressor clutch (C0182) on a BG wire. The compressor clutch (C0182) is earthed on a B wire.

Condenser Fan

The cooling fan relay coil (C0019) is provided a feed by the energised main relay (C0063) on an NO wire. To energise the cooling fan relay, the ECM (C0658) provides an earth path for the relay coil (C0019) on a BP 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.