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

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FFF - 20 Jul 2005 03:30 GMT

After a long trip, 4 hours all highway but got stuck in construction
detours several times, I get out of the car (e46) and the radiator fan
ran on continuously.

Pulled each fuse in fuse panel individually but made no difference.

Pulled each of 3 relays in black box under hood in front of driver, no
difference. Also noticed 5 or six fuses in covered black box 1 inch
square but did not remove them to test circuit for open.

Disconnected battery, fan stopped.

Drove the car back home with power plug to fan disconnected. Temp gauge
showed no tendency to overheat.

What am I overlooking and where is it?

Overheat switch that sends power to fan?

Fan relay? Where is it?

Thanks in advance to all who send help. I have to drive to work
tomorrow. (highway)

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daytripper - 20 Jul 2005 03:51 GMT

>After a long trip, 4 hours all highway but got stuck in construction
>detours several times, I get out of the car (e46) and the radiator fan
>ran on continuously.

[snipped]

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

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FFF - 20 Jul 2005 06:16 GMT

>
>
[quoted text clipped - 7 lines]
>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.

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Jan Kalin - 20 Jul 2005 12:03 GMT

>>
>>
[quoted text clipped - 21 lines]
>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
http://www.realoem.com/bmw/select.do and entering your car's data.

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FFF - 22 Jul 2005 18:45 GMT

>
>
[quoted text clipped - 39 lines]
>
>

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?

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Peter Bozz - 20 Jul 2005 12:38 GMT

> After a long trip, 4 hours all highway but got stuck in construction
> detours several times, I get out of the car (e46) and the radiator fan
[quoted text clipped - 19 lines]
> Thanks in advance to all who send help. I have to drive to work
> tomorrow. (highway)

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?

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fbloogyudsr - 20 Jul 2005 15:14 GMT

"Peter Bozz" <spam@rama.com> wrote

> 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?

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

Floyd '01 330xi

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J Strickland - 20 Jul 2005 18:04 GMT

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.

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FFF - 21 Jul 2005 07:30 GMT

>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
[quoted text clipped - 28 lines]
>
>

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.

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