Operation

OPERATION

Td4

Feed from the positive battery terminal (C0192) is supplied to fusible link 1 and the main relay (C0632) on an R wire. Both are located in the engine compartment fuse box. Operation of the main relay (C0576) is controlled by the Engine Control Module (ECM) (C0603) on a WK wire. The energised main relay provides a feed to fuse 4, which is also located in the engine compartment fuse box.

Fusible link 1 is connected in series with fusible link 7. Fusible link 7 provides a constant battery feed to the starter relay, which is also located in the engine compartment fuse box. Operation of the starter relay (C0576) is controlled by the ECM (C0059) on an RW wire. The relay coil (C0576) is earthed on a B wire. The energised starter relay (C0572) provides a feed to the E-box fan (C0646) on an NR wire.

E-box Fan

Fuse 4 of the engine compartment fuse box (C0575) provides a feed to the E-box temperature sensor (C1258) on an NK wire. The temperature sensor is a thermostatic switch. When the temperature within the E-box reaches 35 °C (95 °F) the switch contact close. Current flows across the switch contacts (C1258) to the E-box fan (C0646) on an NK wire. The E-box fan (C0646) is earthed on a B wire.

When the temperature within the E-box drops to 27 °C (80 °F), the switch contacts within the sensor open, cutting the feed to the E-box fan.

K Series

Feed from the positive battery terminal (C0192) is supplied to fusible link 5, and the main relay on an R wire. Both are located in the engine compartment fuse box. Fusible link 5 (C0573) provides a constant battery feed to the cooling fan relay (C0019) on an SU wire.

Operation of the main relay (C0576) is controlled by the ECM (C0913) on a WK wire. When energised, the main relay provides a feed to fuse 4, which is also located in the engine compartment fuse box. Fuse 4 (C0575) is connected to the cooling fan relay (C0019) by an NK wire.

Engine Coolant Temperature (ECT) Sensor The ECM monitors Engine Coolant Temperature (ECT) via the ECT sensor. The ECM (C0914) provides a feed to the ECT sensor (C0169) on a KG wire. As ECT rises, the resistance of the sensor falls. By measuring the voltage returned from the ECT sensor (C0169) on a KB wire, the ECM (C0914) can determine ECT.

Cooling Fan

When the ECM (C0913) registers a temperature of 102 °C (215 °F) via the ECT sensor, it energises the cooling fan relay by providing an earth path for the relay coil (C0019) on a UR wire. The energised cooling fan relay (C0019) provides a feed to the cooling fan motor (C0005) on an NR wire. The cooling fan motor (C0005) is earthed on a B wire.