Air conditioning - Td5 (page 2 of 3)

Fuse 3 of the passenger compartment fuse box (C0580-6) provides a feed to the blower relay (C0153-3) and the air conditioning unit (C1273-11) on white/green wires. The blower relay (C0153-2) is earthed on a blue/black wire and is energised whenever the ignition switch is in position ’II’. This allows a feed from fuse 9 of the passenger compartment fuse box (C0580-18) to flow across the relay (C0153-1 & C0153-4) to the blower motor (C0023-1) on a blue/white wire.

The blower motor (C0023-2) is connected to the blower motor resistor (C0068-2) and the blower motor switch (C1494-5) by blue wires. The blower motor switch (C1494-3) is earthed on a blue/black wire.

With the ignition switch in position ’II’, the main relay (C0063-87) in the engine bay fuse box is energised and provides a feed to both the compressor clutch relay (C1268-85) and the cooling fan relay (C0019-85) on brown/orange wires. The earth path for the compressor clutch relay (C1268-86) is controlled by the ECM (C0658-29) on a black/slate wire. The earth path for the cooling fan relay (C0019-86) is also controlled by the ECM (C0658-4), this time on a black/purple wire.

The ECM receives 2 inputs from the air conditioning system. The trinary switch (C0279-3) provides an input to the ECM (C0658-9) on a black/slate then yellow/slate wire. This input is the aircon clutch request. If granted the ECM provides an earth for the compressor clutch relay. Current can now flow from fuse 10 of the passenger compartment fuse box, across the energised compressor clutch relay (C1268-30 & C1268-87) and supply a feed to the compressor clutch (C0182-1) on a black/green wire. The compressor clutch is earthed (C0182-2) on a black wire.