Operation

OPERATION

The vehicle has two cooling fans mounted inboard of the radiator. The cooling fans are able to run at two speeds, a slow speed and a fast speed. Operation of the cooling fans is controlled by two temperature switches located in the top rail of the radiator. The temperature switches have different operating temperatures. The low temperature switch operates between 94° and 105° C, and the high temperature switch operates between 103° and 114° C. The low temperature switch connects the cooling fans in series to achieve a slow speed and the high temperature switch connects the cooling fans in parallel to achieve a fast speed.

The cooling fan fuses and the cooling fan relay module are located in the passengers side footwell.

The cooling fan relay is supplied on an N/O wire from the TCIE joint connector, which is in turn fed from fuse 28 in the engine compartment fusebox via the main relay. The main relay is energised when the starter switch is ON.

An earth path for the fan relay is provided on the U/Y wire when the engine coolant temperature has risen sufficiently to cause the low temperature switch to close.

With the cooling fan relay energised, a supply from fuse 55 on a N/G wire is supplied to cooling fan motor 1 on a P/S wire. From cooling fan motor 1 voltage is supplied on a U/S wire, through the normally closed contacts of the change over relay 1 and change over relay 2, to cooling fan motor 2. Cooling fan motor 2 is earthed by a B wire. Both cooling fans are now connected in series and run at slow speed.

The 2 change over relays are internally supplied from the N/O wire. When the engine coolant temperature has risen sufficiently, the high temperature switch closes providing an earth path to the 2 change over relays, energising the relays. With change over relay 1 energised the earth path for cooling fan motor 1 is rerouted directly to earth on a B wire. With change over relay 2 energised, cooling fan motor 2 is fed from fuse 50 on a N/U wire. Both cooling fans are now connected in parallel and run at fast speed.