Air Conditioning Condenser Fan Grant

With the trinary switch normal pressure contact closed, the earth signal is transferred from the trinary switch (C279-3) to earth on a black wire. Completion of this earth path is used by the ECM as a signal to grant the A/C condenser fan.

Air Conditioning Condenser Fan Grant

To grant operation of the condenser fan, the ECM completes an earth path to the condenser fan relay and the cooling fan 1 relay. The earth path from the ECM (C159-5) is applied to the relay module (C173-3) on a blue and yellow wire and completes the circuit for energizing the condenser and cooling fan 1 relays.

The energized main relay inside the engine management relay module (C157-8) supplies a feed on a brown and pink wire which is connected to the relay module on two pins (C173-1 and C173-4). This feed energizes the coils of the A/C compressor clutch relay, the condenser fan relay and the cooling fan 1 and 2 relays.

With the A/C condenser fan grant complete, the condenser fan and the cooling fan are operated in parallel (fast mode), each fan receiving its power supply from a separate source.

A feed from fuse 2 (C572-2) in the engine compartment fusebox passes to the relay module (C172-8) on a brown and white wire. The feed passes through the condenser fan relay whose contacts have been closed by the A/C grant. From the relay module (C172-3), the feed passes on a slate and blue wire to the condenser fan motor (C280-1). The condenser fan (C280-2) is earthed on a black wire.