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Hi, everybody! My name is Rafa; I am from Spain, I'm 20 years old and this is my first message here. Sadly for a problem with my m5. I hope that you will can apologies for my poor English.

Anyway, thanks for made this forum possible with all of your support!


Well, the problem Is about the auxiliary electrical engine fan and the A/A. When the electrical fan doesn't work, the A/A neither works. Up to today, when the electrical fan doesn't start to work when the car was warm (not overheated, always in the middles of both clocks) I unplug and plug it again from the connector and it starts to spin. When it started to spin, the A/A worked perfect but not before so I want to know what could be happen and if the car has some relay that make the A/A and the electrical fan work together.

However, today the fan failded again and i couldn't mede it work unpluged, and pluged and again, the A/A doesn't work. (really the air compresor starts to work but a few seconds later it stop)
 

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I figured A/A was in fact A/C. And if it is hot out the A/C will turn off from too much pressure. The fan pushes air through the A/C condenser which is what cools the A/C refrigerant. You need to have your A/C refrigerant levels checked, you may not have enough by what you are reporting.
For your fan
http://www.m5board.com/vbulletin/e39-m5-e52-z8-discussion/191414-auxiliary-fan-diagnosis-help-please.html
In my thread you will find links to other threads, read them all but the one started by SleeperE39 is very good.

The bottom line is you will likely need a new fan, the ones on the M5 are not repairable. Don't get fooled into buying a 4 wire fan it must be a 3 wire fan. The part number is in the other threads.
 

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Discussion Starter #4
I figured A/A was in fact A/C. And if it is hot out the A/C will turn off from too much pressure. The fan pushes air through the A/C condenser which is what cools the A/C refrigerant. You need to have your A/C refrigerant levels checked, you may not have enough by what you are reporting.
For your fan
http://www.m5board.com/vbulletin/e39-m5-e52-z8-discussion/191414-auxiliary-fan-diagnosis-help-please.html
In my thread you will find links to other threads, read them all but the one started by SleeperE39 is very good.

The bottom line is you will likely need a new fan, the ones on the M5 are not repairable. Don't get fooled into buying a 4 wire fan it must be a 3 wire fan. The part number is in the other threads.
So, all the problem is the fan as I can see.

I think my A/C levels are perfect because when the fan works, it make the cockpit a freezer.

Anyway, I'm reading your link but, could be the reley the problem? Is a little bit strange that when you unplug and plug it again, it sometimes works.

I tested the voltages in the connector and it gives -12/-14 volts (car off/car on) It is correct?
I don't know why with red with red and black with black cables it gave me a reverse (negative) polarity.


Thank you very much!!
 

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There are three wires and no rely. The two fat wires are ground and power. Black is + and brown is -. The small wire, yellow/red, is a signal from the DME which tells the fan what speed to run at.
Not all speeds will be screwed up. Likely part of the board inside the fan is damaged but some maybe good. That is where the pulse comes from. Mine also pulsed and sometimes would come on, at least when I first bought my car.

As you can see the power can go to the motor from different points. You could see if the pics were better. In the bottom pic just inside the windings are terminals. By sending power through different terminals you get different speeds.
This is why the fuse 75 blows, because the high speed might still work, but without the fan spinning the power demand is too high.
AuxFan1.jpg

AuxFan2.jpg

AuxFan3.jpg
 

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Discussion Starter #6
Ok. There was the reverse polarity problem.
Can I test my fan connecting a battery directly to the black and brown wires?

If with this it doesn't work, is for sure the electrical engine?

Here in Spain I saw replacement engines. Why did you say that the fan couldn't be repaired? If I buy a new engine and I put it where the old was, what is the problem?

Thanks again :)
 

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That is from a 5XXi car the M5 got the upgraded E38 system. So you need a direct replacement for a M5 or E38 the other E39 fans won't work. They have a resistor pack and a relay and 4 wires.
To test the fan you can hook up 12v to the black and brown wires, then you need to be able to feed the yellow wire a pulsed voltage. Just test the yellow wire for v with the car running. If you get volts there then you can be sure the fan is toast.
 

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It is not the motor that fails it is the board that burns. Those motors you see are for other E39s not the M5 which is a E38 fan.
 

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That is from a 5XXi car the M5 got the upgraded E38 system. So you need a direct replacement for a M5 or E38 the other E39 fans won't work. They have a resistor pack and a relay and 4 wires.
From what I have found and verified with realoem all e39 5 series cars use the same part number pusher fan.

64546921395

Pusher fan

<DL> <DT>From:</DT> <DD>03/01/2005</DD> <DT>To:</DT> <DD>-</DD> <DT>Weight:</DT> <DD>4.110 kg</DD> <DT>Price:</DT> <DD>$374.55</DD></DL> Supersedes:

<DL> <DT>64546921946</DT> <DD>(11/05/2001 — 05/24/2005), Exchangeable retrospectively</DD> <DT>64546919057</DT> <DD>(05/31/2001 — 10/17/2001), Exchangeable retrospectively</DD> <DT>64506908030</DT> <DD>(11/22/1999 — 06/26/2001), Exchangeable retrospectively</DD> <DT>64548380781</DT> <DD>(05/01/1998 — 11/24/1999), nonexchangeable retrospectively</DD> <DT>64548380780</DT> <DD>(05/01/1998 — ), Exchangeable retrospectively</DD> <DT>64548370993</DT> <DD>(09/01/1995 — 06/09/1998), Exchangeable retrospectively</DD> <DT>64548371362</DT> <DD>(09/01/1995 — 02/01/1996)</DD></DL>
Part 64546921395 was found on the following E39 vehicles:
 

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That is the problem there is bad info on realOem. Read Robs comment here http://www.m5board.com/vbulletin/e39-m5-e52-z8-discussion/191414-auxiliary-fan-diagnosis-help-please.html he has the 540 body and fan. His is a four wire fan. Further down the page Terrabass was sold a four wire version. The list goes on.
I had the problem with the AUX FAN last year.

I decided to buy the used working one from scrape yard.
Of course they did not have an M5 fan, but they had both 3 wires and 4 wires plugs.

I chose the 3 wires plug. It worked for 1 season.

Now it does not work after the winter.

Why I am saying this: I did not know then when I bought the used one that only the specific M5 fan will work.

But, as you see from my story, it did work.

Now, I am planning to buy a new one - OEM from BMW. I use ETK (realoem) to order the parts. If it shows a part number according to my VIN, and then as you can see from the previous messages that the very same part number is found on 520i - 540i etc...how can I choose the right fan?

ETK and car's VIN are ultimate judge for me, but I also know that people here on this board know so much about these cars.

Let us clarify this please before I waste another couple of hundreds on a new aux fan.
 

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I ended up buying 60 and selling 59 so I am not sure what the part number is. The number AGM posted was posted in my thread but I am not sure. I will find out.
 

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Discussion Starter #14
That is from a 5XXi car the M5 got the upgraded E38 system. So you need a direct replacement for a M5 or E38 the other E39 fans won't work. They have a resistor pack and a relay and 4 wires.
To test the fan you can hook up 12v to the black and brown wires, then you need to be able to feed the yellow wire a pulsed voltage. Just test the yellow wire for v with the car running. If you get volts there then you can be sure the fan is toast.
Well, I have been tested this without results. I have videos and photos.

First of all I turned on the car and whit the A/C on I unplugged the fan, connected yellow from the fan to yellow from the car and put voltage directly to the fan. It didn't work. I'm doing it correctly? In the first photo you can see the contention between yellow wires and in the second one, applying voltage.

Then I recorded a video where you can see that when you plugged it, it almost run... But it didn't do :cry:
http://youtu.be/Dv2_VYsHmHI

So, definitely, do I need to buy a new fan?
 

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Fan seems to be logical. You might find an open circuit if you use ohms and test the fan side of the yellow and ground. That would be a very strong indicator.
 

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