Radiator Fan Wiring

[bcmc33]

I am planning next winter?s work which will include a new aluminium radiator and multi blade fan. I already have the fan which can suck or blow, so I have some time before deciding which side to fit it. However, the circuit diagrams I have do not include an electric fan, but the write-up does say that the power supply should come from an ?ignition live? connection.
I find this strange as I automatically assumed that it should be a permanent live supply with the switch making/breaking the earth connection. This enables the fan to run after the stopping in order to address any latent heat build-up.

All comments welcome.


Brian Clarke
(1972 Sprint)

[msd1107]

Depends on the manufacturer of your fan.

The theory behind putting it on an ignition live circuit is that when the ignition is off, the engine is off, so no water is circulating and running the fan has little benefit.

If you have gone to an electric water pump, you can set up the water pump to keep running after shut off, until the engine water temperature comes down to a certain temperature.

Then you would want the lead to the fan to be always on, to keep the fan running till the engine coolant had come down.

David
1968 36/7988