Help needed with 99 e46 cooling fan runs continuously after key removed

why do you think this isn't entirely normal behavior?

I guess I did not give enough details, even after the engine was cold, the fan would continue to run, The battery would eventually exhaust itself if I did not disconnect the power to the fan. It is NOT normal behaviour because after 48 hours of not using the vehicle, I plugged the connector back in and the fan continued to run with no key in the ignition.

Disregard my request for help. I started disconnecting all sensors on the engine with the fan running, 5 hours after I shut the engine down (engine cold) I found that the connector at the front of the engine lined up parallel to the axle just under the valve cover did the trick. I reinserted it and the fan shut off. I wish I knew which sensor this was. It is also located on the exhaust side of the engine.

Logic says it measures water temperature. From behaviour I'd say the sensor's resistance increases with temperature, so with the connector off (infinite resistance) it assumes that nuclear fusion is taking place in your engine and it attempts to cool it down.

You can check out parts for your car by going to

I thought the radiator fan was mounted on a viscous clutch: cold engine, grip (no turn), warm engine, slip (and turn).

Wouldn't this be your auxiliary fan?

"Peter Bozz" wrote

E46 with M54 engines don't have fans mounted on the water pump; they have two electric fans.

Floyd '01 330xi

That fan is thermostatically controlled. Let it run until it shuts itself off. It can run for as long as it takes. If it is still running after an hour, then I'd be concerned, but then I'd watch it to see if it repeats.

The same problem returned today. After disconnecting the fan power connector I let the engine cool off with the hood open. 4 hours later , when I reconnected the power to the cooling fan, it ran again with no key in the ignition and engine not running.

There must be a relay that the control circuit closes, this relay may be welded closed or the control circuit is telling the cooling fan to run. Any one know where the thermostat or temp switch for the control circuit is? Anyone know where the relay for the cooling fan is? There could also be a fault in the wiring harness that tells the control circuit that the cooling fan should run.

In any case, the car runs at normal temperature with no cooling fan connected electrically. Of course I did not idle or remain stationary for any length of time. I suspect this is when the cooling fan would run. The cooling fan has never operated with the engine off for as long as I have owned the car, for several years.

I followed the link but was unable to find any data that would help. At this link there is an ad to sell trouble shooting manual but after paying the $18.99 was unable to download the manual and the contact us link where I sent two questions was also ignored, I cancelled my order because I need my car and can't wait around while the internet gods work to complete transactions.

Still driving around with no fan .................................. overheat?