E46 320D 2000 electric fan does not switch off, runs all the time. Connector voltage? - BMW Forum

spacemanwayne · 09-13-2009, 09:37 AM

Hi guys

Hope you can help. My electric fan runs all the time, so i have to pull out the big 50 amp fuse everytime. I sent it to BMW but i am not convinced they fully diagnosed the issue. The fan remains on whether the a/c is on or off. I have done a test on the voltages going through the connector that goes to the fan shroud. I did it the next morning so the engine was cold.
I am referring to the connector which powers the electric fan, there are 3 wires, the one is main power(red), the other is earth(brown), there is also a black/green wire and this is the wire i am trying to figure out, i think this is the signal the system sends to the fan to control the speed, am i correct? And i assume the higher the voltage the higher the fan speed.
I disconnected this plug from the fan, and used a multi meter plugged into these wires. Positive from the meter connected to the black/green wire and earth on the brown wire. The voltage is around 5.6volts on this wire and when just started, and when the temperature gauge reached maybe just one needle width passed exactly half on the gauge, the voltage was around 5.8v. Is this normal, i was expecting a rather large variation. I tried googling and could not find anything.

Any help on this matter is appreciated

Thanks
Wayne

witeshark · 09-13-2009, 09:41 AM

My first look would be for a stuck relay. Many cars have the electric fan powered regardless of the ignition switch so it can cool the radiator in the odd event that it's over temp spec after shutting down.

spacemanwayne · 09-13-2009, 09:45 AM

Hi whiteshark

Thanks for the reply. Where can i find this relay? I look at the fuse box but there is nothing for it, there is just the 50Amp fuse.

Thanks
Wayne

witeshark · 09-13-2009, 10:03 AM

Maybe diagrams from realoem.com can help.

spacemanwayne · 09-13-2009, 12:01 PM

Hi Witeshark

Thanks for the website, its very useful!!! I had a look there, and cant find anything though. I also looked around at other forums and it appears that this relay is part of the fan shroud and it cannot be replaced seperately. It is also referred to as the final stage controller, correct me if i am wrong. I tried to source this part from Bosch but they dont have it listed, must be a bmw bosch thing.

As for my problem, I think this is what bmw has concluded is broken. I was hoping to find out if the voltages going to this unit on my car was in the normal range, if someone could confirm what i measured and got was indeed normal, i will go get a new fan. I am worried about replacing the fan, which cost 2 arms, a leg and a tooth and the problem is still there

.

Kind regards
Wayne

witeshark · 09-13-2009, 12:27 PM

At this point, you've exceeded what I know about that car and those components...

spacemanwayne · 09-14-2009, 09:45 AM

lol

I will still update this post though as i go along through finding the solution to this problem i have.
thanks for you help though

witeshark · 09-14-2009, 10:06 AM

Best of luck with it!

gemnilvr · 11-07-2009, 03:18 PM

hello, i know its a little late but it is a common problem and it is the blower motor unit or also called the fsu - final stage unit! its an easy diy project!! the part is about $75 and takes about 30 min!! good luck!!

CanadianWraith · 11-08-2009, 07:52 AM

Quote:

Originally Posted by gemnilvr

hello, i know its a little late but it is a common problem and it is the blower motor unit or also called the fsu - final stage unit! its an easy diy project!! the part is about $75 and takes about 30 min!! good luck!!

uhhh......no. the fsu is for the climate control unit inside the car

gemnilvr · 11-08-2009, 09:53 AM

Quote:

Originally Posted by CanadianWraith

uhhh......no. the fsu is for the climate control unit inside the car

The original post states that the fan was continuously running! The fsu controls the fan and this fixed the problem I was having with my car when the fan was running while the car was off! It was also keeping my car from going into sleep mode so the orange light next to the shifter would stay on. All I'm saying is it's a common problem and could be good information for someone having these problems.

CanadianWraith · 11-08-2009, 10:04 AM

the fsu controls the blower motor fan not the cooling fan for the motor

gemnilvr · 11-08-2009, 10:19 AM

Yeah, I thought this was the fan they were speaking of bcuz they said the fan stayed on with the a/c on or off! My bad!

CanadianWraith · 11-08-2009, 12:11 PM

no biggie