Fan won't turn off after turning the engine off.

[zulfur]

Hi everyone,

I have a problem where the fan somewhere by the radiator won't turn off after I shut the engine off. This is for my 1995 e34 530i.

I was wondering if anyone knew the name of the fan or can point me to the right direction. The problem happens every few days, and if i disconnect the battery and reconnect it, the fan will continue to spin.

http://www.youtube.com/watch?v=tr1tLWqWU90

Things attempted:
1. Pulled AUX fan fuses.
2. Pullled temperature sensor connector off the radiator
3. Pulled AUX fan relays (yellow, green).

None of the above shuts off the fan.

[E346]

That sounds like your auxiliary fan sir, its electric while the main engine fan is mechanical. It could be a faulty temp switch for it, anyone agree? You can pull the fuse for it in the meantime, but it could cause overheating if you use the A/C in cali...

[ingsoc747]

Hi everyone,

I have a problem where the fan somewhere by the radiator won't turn off after I shut the engine off. This is for my 1995 e34 530i.

I was wondering if anyone knew the name of the fan or can point me to the right direction. The problem happens every few days, and if i disconnect the battery and reconnect it, the fan will continue to spin.

I've only had my 530i for a little while, but I know that on my Acura, if the engine is still too hot, the fan will continue to run for some time after the car shuts off... maybe this is the case with the BMW??? :confused

[zulfur]

I pulled out the fuses (25,29) for the auxiliary fan, but that didn't shut down whatever fan was spinning.

If I reconnect the battery in the morning when the engine is completely cool, it will resume spinning as well.

[wastedincome]

It DOES sound like the AUX fan, I'd say its a faulty temp switch located on the side of your RAD.
HTH

[zulfur]

I pulled out the yellow and light green relays related to the Auxiliary radiator cooling fan, but that didn't shut off the fan. Any other things I could try?

I tried pulling out the Auxiliary radiator cooling fan temperature switch connector (3-pronged) but it didn't shut off the fan.

[M Quick]

Pull the fan connector from the temp sensor.
I would suspect a bad temp sensor aswell.

[zulfur]

Pull the fan connector from the temp sensor.
I would suspect a bad temp sensor aswell.

I tried pulling it from the radiator, it didn't shut it off.

[M Quick]

Then remove the fan connector that goes directly from the fan. If that doesn't turn it off, then you got a fan with it's own life! Hehe.

I would meassure the pins of the connectors too and see where the power is coming from. And ofcourse follow up on the wires to check after any damage.

[zulfur]

I'm starting to suspect that it's the control module for the aux cooling fan which is built into the fan. Unfortunately I can't readily get to it to pull it out and inspect it.

http://forums.bimmerforums.com/forum/showthread.php?t=1283206

[zulfur]

Turns out it's the smog pump which stays on.

[shogun]

smog pump? Never heard of such thing. Is that special for U.S. models? Any pics?