# 03 e39 530i 13th gen bt ulf alernator whine



## Scotes (Jan 12, 2002)

I have a 12/02 build 2003 e39 in which I recently installed the 13th gen bt module from bimmernav. I have a retrofitted nav system with two amps tied into the 12 & 26 pin connectors in the trunk. Prior to installing the bt ulf I had no alternator whine / noise in the system. After plugging in the ulf I now have a faint alternator whine and I am trying to figure out how to get rid of it.

As I have the euro armrest I did not install the tray and only have a hack momentary button for pairing. With the euro storage tray in the armrest there really isn't room to keep the button plugged in so that connector is open. I thought that this might be an issue but keeping the button assembly plugged in does not solve the problem.

As I noted I have a set of amps powering the stereo. These are pulling power off of a direct connection to the battery with a separate single ground to the chassis. As the ulf ties into the oem audio system harness and it is not tied into the same ground used by the amps I think that is causing the open loop. So I think if I tie the two grounds together it should solve the problem.

I would just tap into the ground wire going to the ulf in the 54 pin harness and run a line to the ground used by the amps. Or, would it be easier to run an additional ground wire from the ground block the amps are connected to to ground point in the 12 pin connector? This would certainly be easier.

Any help on this would be greatly appreciated! Thanks!


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## Scotes (Jan 12, 2002)

Anybody got any thoughts on this?


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## Evilsizer (Apr 4, 2008)

you say tied 2 amps in are these after market amps i take it? my thought is something with the grounding might be doing on... other wise you may need to a filter of some kind to kill the whine.


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## Scotes (Jan 12, 2002)

Yes. I've removed the oem amp from the non-dsp system and tapped into the 12 and 26 pin connectors to two aftermarket amps. Both amps connect via 8awg wire to distribution blocks for power and ground and then power is connect 4awg to the battery and ground 4awg to the chassis. Prior to putting in the ulf there was no noise in the system.


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## Evilsizer (Apr 4, 2008)

well im still back to a grounding issue, possibly with the ULF installed...im just not sure what else to suggest right now. maybe someone else has been thru this and will chime in.


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## Scotes (Jan 12, 2002)

Right - my understanding of alternator whine in stereos is that it generally comes from an open ground loop. Anyone want to correct me there? If I have two pieces of kit - the aftermarket amps and the ulf - both tied into the same audio chain but grounded to different points that is causing the problem.

So let me ask part of the question a different way - If I add an additional ground wire from the aftermarket amp distribution block to go to pin #3 on the 12 pin connector (which is the ground pin for the oem stereo amp and is currently not used) while leaving the other main ground for the aftermarket amps in place will I cause any damage to anything. If not I will just give it a try and see what happens. Essentially grounding to two different but common points.


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## Evilsizer (Apr 4, 2008)

no you wont hurt anything ground is still ground, no matter where its coming from. i think your going in the right direction by tappin into the other ground.


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## tekkumala (Dec 11, 2007)

I am having the same exact problem with the 13th gen ULF in my 2003 530i 5speed. My stereo system is also aftermarket amp and preamp. It was already installed when I purchased it a month ago. I just installed the Bluetooth ULF yesterday and now with the whine. Did you find any solution?


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## Scotes (Jan 12, 2002)

I've not gotten around to trying what I was going to try but I was going to try tomorrow (say that five times fast...). I think tying the ground from the aftermarket amps to the ground on pin #3 of the 12-pin connector will solve the problem. As the amps are grounded to a different location than the ULF, which ties into the audio chain, it is creating an open loop. By running an additional ground between the two this may close it. We'll see.


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## Scotes (Jan 12, 2002)

Ok, so I ran a wire from my amp ground distribution block to pin #3 on the 12-pin connector and while it dimmed the whine a tiny bit it is still there. Just to reconfirm it is the ULF I disconnected it and bam - whine all gone but of course not bluetooth. 

So it definitely is the ulf module causing the whine. My only other thought is to run a wire from either the amp grounding block or the 12-pin connector to the ground wire on the 54-pin connector that connects to the ULF. Can anyone advise which wire is the ground wire there? Dumb thought but is it just the brown one?

Anyone else got any thoughts?


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## Scotes (Jan 12, 2002)

Some more info I posted over at x5World on some more testing I did tonight...
Ok, so I did a little more testing tonight. Here's the results...

- With everything connected I entered Voice Recognition mode and the whine is still there. The whine is there radio on or off, in VR mode, or in phone mode.
- I disconnected the sub amp which is in the oem amp location and no joy - whine was still there.
- I then disconnected both amps and reconnected the oem e39 amp to the 12 and 26 pin connectors. The whine was still there but very very faint - it was at a level I would be happy with. Down side is the oem amp sounds like ****e compared to the Alpine I am running.

One odd thing about reconnecting the oem amp was the level of the amp. I could turn the volume down real low and still hear something. The lowest (or highest; don't know how you refer to it) gain setting on the Alpine is 4v which did not give the same precise control the oem amp gave. It was almost as if the oem amp was running a gain of 5v or 6v.

Thoughts??


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