Auxiliary Radiator Fan

[rwagner735]

1989 325I Convert. (new to me) Auxiliary Air Fan. Doesn't run when A/C turned on. Fan OK, checks out from relays and radiator temp switch. Also, should fan run when Recirculation button pushed. Bentley wiring diagram doesn't go far enough to trouble shoot. Anyone have experience and / or wiring diagram?

 

[jimhorton1963]

as far as i know the aux fan should run when the ac is turned on. the recirc. should not effect the fan. does your compressor run when the ac is turned on?

 

[southpaw]

Check the resistor located on the Aux. fan housing. It is used for normal speed operation and is bypassed for high speed when the coolant temp. switch on the radiator closes at high temps.

 

[jlh]

This works on '87 325i. Worth a try.
The recirc switch brings on the cabin fan low speed in the recirc position.
The A/C switch when depressed and glows blue (must have the floor or dash vents open)
closes the aux fan low speed relay and fan runs.
This test can be done with the ignition in run position but the engine does not need to be running.
To test the comprssor clutch to see if it engages then the engine must be running.