Aux Cooling Fan troubleshoot?

[Jehu]

I was greeted the other day by myaproximately One year old Made in Germany Aux Cooling Fan suddenly going at High RPM the moment I turned the Key to Position #2 when about to start the car. The air temp at the time wasn't even 90 F.

I removed the radiator sensor plug to jumper and see what was up. I got High but no low rpm.. when I jumper the Low wire I hear the Relay clicking but the Fan doesn't spin. Is the Resistor failed? I actualy went and bought a brand new relay from BMW but may not have needed it. The wires in the relay box leading to the low speed relay all appear intact but I haven't used a volt meter or ohm meter to check anything . oh and the two fuses are OK. Any ideas?

[bimmo_2007]

I was greeted the other day by myaproximately One year old Made in Germany Aux Cooling Fan suddenly going at High RPM the moment I turned the Key to Position #2 when about to start the car. The air temp at the time wasn't even 90 F.

I removed the radiator sensor plug to jumper and see what was up. I got High but no low rpm.. when I jumper the Low wire I hear the Relay clicking but the Fan doesn't spin. Is the Resistor failed? I actualy went and bought a brand new relay from BMW but may not have needed it. The wires in the relay box leading to the low speed relay all appear intact but I haven't used a volt meter or ohm meter to check anything . oh and the two fuses are OK. Any ideas?

Yeah, it's possible! Check the Resistor and the low speed supply.

[Blitzkrieg Bob]

Got a meter?

check to see if the resistor is fried... Had the same thing a while back and it made me for a day trying to figure it out

[Jehu]

Thanks gents. I can get a meter and may be just source a replacement resistor and splice it in and see anyway.

[bmwrp8]

Thanks gents. I can get a meter and may be just source a replacement resistor and splice it in and see anyway.

had a similar problem too 2 weeks ago turned out to be the socket of the aux fan was not making contact so i cleaned it. Was brittle too and whenever the fan turns high mode socket becomes abnormally hot so im looking for a replacement socket.