2002 e46 radiator fan will not stop running

[gmeyers5]

Thanks in advance for any advice you can offer. A few weeks ago, my radiator fan spontaneously came (the car parked in the garage). Since then the fan runs continuously. I unplugged it to save the battery.

Some searches have suggested:

1) the temperature switch - but not sure where it is
2) the relay

[Podmore]

I'd go for the relay - it's the only thing that could cause the fan to continue running after the ignition is switched off.

[steweydoogan]

Happened to me and had to replace the fan, but check the relay first they only cost like 10 bucks

[gmeyers5]

Thanks. This is helpful. Dealer wants to sell fan and relay as an assembly. Where can I but the relay separately?

[choffa]

Relay is most likely a standard Bosch or Siemens part. Check the on-line vendors, or a good local import parts store. Common relay usually. Sometimes a good smack will free the contacts inside (welded together). If the relay can be opened (it might be sealed shut), you can often polish the contacts & breath a bit of life into it, like filing ignition points for us old farts.

Color coded:
http://www.pelicanparts.com/bmw/cata..._pg2.htm#item6

[gmeyers5]

Perhaps I'm looking at the wrong thing. There is a small metal box with plastic cover mounted on the lower left hand side of the fan. The electrical connector with control wire, power, and ground go into this box. I assumed this was the realy. However, this does not resemble the typical looking relay's avaialble through the link you sent.
Should I be looking at something else? If so, where?

Thanks in advance.

[thejlevie]

I think that fan may be the variable speed variant rather than the two speed type found on earlier BMW's. The variable speed variant has a PWM speed controller at the fan and is controlled by the DME. A failure in the PWM controller can cause the fan to run all the time and the only fix is to replace the fan.

[erfont]

its the fan. the green transistor built in is burnt

[Kraizevoodoo]

hey i'm having the same problem. but these relay on that link dont match the one i have

here is a picture of mine

[stanley]

Needs fan assy, also a fire hazard, they are known for that. Part of SB.
In addition, it is possible in some cases for the failure of the electrical circuitry to cause smoldering. In the extreme case, a fire in the fan control unit, which is mounted in the fan and located in the front of the engine compartment, could occur. This could happen either while the engine is running or after the ignition has been switched off since fan may run for up to 11 minutes after engine shutdown.
AFFECTED VEHICLES

[nathancarter]

hey i'm having the same problem. but these relay on that link dont match the one i have

here is a picture of mine

Your photos show the wiring harness; the relay is the electrical component that controls when and if the fan runs. It's the little box on the front of the fan assembly.

Unfortunately, on the E46, the relays are not available separately from the fan, so unless you're an electrical wizard, you just replace the whole fan assembly, to the tune of about $400.

There was someone recently who found a supplier who carried the fan without the relay box, so presumably one could find the relay box without the fan. I don't think anyone has found a supplier for said relay box yet.

I was fortunate - the previous owner replaced the fan assembly right before I took ownership of my '02 330i.

[turbovrGTI]

likely the fan-they typically short internally..

[bmwdirtracer]

Krazivoodoo: You haven't said the year and model of your car, so the only clue I have to your car is the plug you've shown. And that plug matches that of a car with no external fan relay whatsoever, but rather a circuitboard controlled by the dme, as mentioned above several times. +1, you need a fan assembly.

[Kraizevoodoo]

ok i have a 2000 323i.

so your the part i need to replace is below this?. if i follow the wiring down it goes right to the fan assy / motor.

[bmwdirtracer]

That was fun....just did a quick research at BMW-Planet.com 's library wiring diagrams on your car.

It would appear that you have an old-style fan, with 2 speeds and a relay, as others suggested above, not the new style, dme controlled fan.

If you want to do the research (I got tired), go to the above site, load the Adobe reader it requires, go to your car, then to component views of the low speed and high speed relays for the fan. Then with fan running when it's not supposed to be, tap on both those relays with the butt of a screwdriver. If tapping on one of these 2 relays shuts fan off, replace that relay. If not, I'd probably replace the low-speed relay first: as I recall, the high speed relay only gets power through the low speed relay.

[QM E46 328i]

Thanks in advance for any advice you can offer. A few weeks ago, my radiator fan spontaneously came (the car parked in the garage). Since then the fan runs continuously. I unplugged it to save the battery.

Some searches have suggested:

1) the temperature switch - but not sure where it is
2) the relay

Hi. I have the same problem with my 2000 E46 328i Manual Transmission model. What did you end up doing to rectify the constant running fan problem? Do you have the manual transmission model with the Electric DME control fan? What was the verdict? I am constantly placing and removing the 50 Amp fuse on mine to save battery.

Thanks