LKM issues

[LunatiC]

Hey everyone,

I've read on here that it's a common 'trait' of E34s for the solder joints around the relays in the LKM to dry out, causing check control messages for lights and other things, and in more severe cases, the dreaded 'disco lights' phenomenon.

I've been getting the messages pop up whenever I turn my lights on (parkers or low beams), the check control complaining about (usually) licence plate lights and tail lights, and (more rarely) low beams as well. Whenever I go to check the lights though, they are all fine so I just ignore the messages, until I decided I needed to do something about it.

I pulled out my LKM (I have a 525i build 04/1995), opened it up and discovered that the circuit board inside looks very different to the ones I found on the net –*only 4 small relays and a lot of microelectronics (tiny resistors and capacitors as opposed to the more generic larger ones). None of the solder joints from what I could see were dry at all; nevertheless, I resoldered the relay joints and plugged the LKM back in and I'm still getting the same issue.

Does anyone else have anything else to suggest what might be the cause and how to fix this? I haven't ruled out getting another LKM, in the case that I do, do I have to make sure the spare part ispulled from an E34 of similar vintage? Is there a year range of LKM that I should keep clear of?

Thanks in advance guys!
Cheers,
LunatiC

[Bill R.]

Try the ccm instead of the lkm. If your only getting warnings but the lights are fine then the problem is most likely in the Check control module not the light kontrol module.

[shogun]

Australia version?
Do I understand it correct that all works well but that you get warnings in the check control?
Does Australia version have automatic headlight aim?
If so, disconnect the connector from the automatic headlight aim motor behind the headlights in engine room.

Common problem in Europe, when the headlight motor gets older it draws different/too much power and that makes the check control module nervous.
One solution here on the German 7-forum
Sinnlose Fehlermeldungen durch Leuchtweitenregulierungsmotoren --> Die Lösung! (http://www.7-forum.com/forum/24/sinnlose-fehlermeldungen-leuchtweitenregulierungsmotoren-loesung-79879.html)


in case the ccm is defective, here are the important pics in a German instruction
http://www.e34-welt.de/tips_tricks/Reparaturanleitung%20CCM%20e34%20e32.pdf

Resolder R60, R61 and R62 as shown on page 8 of 16

[LunatiC]

Hey guys,

Thanks for the great response! I'll try disconnecting the headlight motors first and see how I go. If I still get the issues, I'll pull out the CCM and see if there's any soldering required in there.

Thanks!

[LunatiC]

Hey so I know it's been ages since I replied, I found a really cheap CCM so I swapped that out first (still had headlight motors connected though) and was still getting the same messages pop up.

After a few months (I know, I know), I finally decided today that I will disconnect the motors since the messages were now quite annoying. I struggled a bit to get them off (snapped a clip too :() but got them off, have ziptied them somewhere in the engine bay and I'm not getting messages any more. I'll see how I go with the cold starts in the morning (it's winter here in Australia), but so far so good.

[Paul in NZ]

the license plate errors can also be the wire loom on the boot hings shorting cos the insulation has cracked where the wires bend every time you open and close the boot

[Ferrett 1962]

I had the same issue with my 08/95 build 525 I got license plate , tail light and dip beam messages but since I pulled the adjuster wires I have had no problems.
I do remember reading somewhere that certain batch numbers of these motors were prone to this problem, I have never had to use the adjustment anyway but I will try to fix the problem if I have any reason to pull the lights out in the future but won't bother untill then.

[LunatiC]

the license plate errors can also be the wire loom on the boot hings shorting cos the insulation has cracked where the wires bend every time you open and close the boot

I suspected that this could also be the case, it makes absolute sense. I'll see how I go with the motor wiring disconnected, if I still get the messages I'll tackle the loom in the boot.

[LunatiC]

I had the same issue with my 08/95 build 525 I got license plate , tail light and dip beam messages but since I pulled the adjuster wires I have had no problems.
I do remember reading somewhere that certain batch numbers of these motors were prone to this problem, I have never had to use the adjustment anyway but I will try to fix the problem if I have any reason to pull the lights out in the future but won't bother untill then.

I'm not terribly fussed with the adjuster motors, my E34 doesn't have a trailer hitch which is probably the only reason you'd need the adjuster motors for. The next owner (if there will be one) would probably wonder why there's wires hanging around in the front of the engine bay and/or wonder why a thumb wheel in the dash doesn't seem to do anything, other than that all good here.

[genphreak]

I really like the adjusters, find it makes highway driving much nicer, tow bar or no tow bar. Certainly don't get issues on my later 90+ e34s. The e28 and '88 e34 get spurious bulb out errors- will have to put new adjuster motors in to check the theory about the older ones going funky. I suspect they go wrong quicker in Europe.

[Ferrett 1962]

I remember reading somewhere there was a short production series that were prone to this issue. I will have to pull some of the front end apart to realign some things when my new bonnet gets here , the small accident damage by the P/O was fixed by an idiot and half the grill does not sit right so I might go further and find replacement adjusters while I am at it and do the whole lot over a weekend. I have some ccfl angle eyes I might try and fit ( my car is grey and with the dim light of winter I want to be seen) I also noticed the connectors had build up in them so I might just try a good clean first to see if that makes a difference.

[LunatiC]

Update - it's been a few days now and no more messages.