Air conditioning (page 2 of 3)

Fuse 17 (C581-14) supplies a feed to the blower relay coil (C817-86) on a green wire, and the compressor clutch relay coil (C1213-86), also on a green wire. The blower relay coil (C817-85) is earthed on a black wire. The earth path for the compressor clutch relay coil (C1213-85) is controlled by the ECM (C634-1), which is connected to the relay by a blue/black then black/slate wire.

The now energised blower relay (C817-87) allows current to flow to the blower motor switch (C275-5) on a brown wire. The blower motor switch is a 3 position switch. Slow speed is attained by turning the switch to position 1. A feed can now flow from the switch (C275-3) to the blower motor (C848-1) on a blue wire. As the current has to flow through the 2 in-line resistors before reaching the motor itself, a slow motor speed is attained. The motor is earthed (C1215-1) on a black wire.

Turning the blower switch to position 2 allows a feed to flow from the switch (C275-1) to the blower motor (C844-1) on a green wire. As the current now only has to flow through 1 in-line resistor, a medium speed is attained.

For high speed operation, turning the blower switch to position 3 (C275-2) allows current to flow direct to the motor (C845-1) on a red wire without having to flow through the in-line resistors. As in the case of low speed and medium speed operation, the blower motor (C1215-1) is earthed on a black wire.

Once the blower motor switch has been turned to position 1, it also allows current to flow (C275-4) to the interlock relay coil (C153-4) on a blue/yellow wire. The relay coil is earthed (C153-2) on a black wire. The interlock relay is also energised when the blower switch is in position 2 and 3.

Although the blower will operate with the ignition on, the air conditioning system itself will not operate until the engine is running, and a number of conditions are met.