Brake, tail, number plate and dip light warning won't go away

[Reidal]

Guys, thanks for the replies. I was begining to wonder if I was the only one.

I have not yet found the answer either. Since my last post I have:
1) checked the trunk hinge wiring (looks ok)
2) been around all the bulb connections with a fibreglass cleaning pencil
3) checked the rearward wiring through the back of the trunk

I have now begun to pick my way through the wiring diagrams to try and work out where all these lights have common circuitry. The odd one out is the dip beam, which makes me think it must be the LKM or it's feeder wiring or alternativly, a positive power feed/fuse etc.

I'm hoping this one won't beat me

[Elekta]

I had a very similar problem to this - it was the headlight levelling motor seized up. I only found it because I had the lights on and engine not running and walked around the front of the car, I could hear the motor grinding away at some length. To diagnose the problem, I just unplugged the motor (near the bulb backs) and the problems went away.

Your mileage may vary, of course.

I recently replaced the motor and all has remained fine.

Damian

It kills me that this was my issue for my warning woes. I had changed both my rear wiring harnesses, my brake light switch and my license plate lights before my indy started on a test rampage that indicated my headlight levelling motor was causing the warning.

I still have my old touring harnesses with rear fog lines in a box in the attic.

Hey, when are we going to see your 540iT? get a photobucket.com acct and host some pics whydoncha?

[Reidal]

Hi Guys

The top score goes to Damian and Eri for highlighting the Headlight leveling motors (but thanks to every one else for their valuable input ).

I carefully checked them some time ago and found they worked perfectly. Twiddle the knob, headlights go down. Twiddle the other way and headlights go up.

Ahh I thought, these are not the problem (WRONG).

Revisited and this time disconnected the motors. Warning lights have not reappeared in approx 3 hours of night driving where they would appear within 15 minutes previously.

I will now try and work out how apparently perfectly operational motors can cause the spurious warnings experienced. I suspect electrical noise is being fed back into the lighting circuits from the motor commutators.

Thanks again Guys. I know my car far better now than I did 3 weeks ago.

[Elekta]

I will now try and work out how apparently perfectly operational motors can cause the spurious warnings experienced. I suspect electrical noise is being fed back into the lighting circuits from the motor commutators.

Let us know what you figure out. I thought I was leaving perfectly functioning light levelers disconnected just to get rid of an error message.

Mine are still disconnected

[Unregistered]

Hi Guys

<DELETED>

Ahh I thought, these are not the problem (WRONG).

Revisited and this time disconnected the motors. Warning lights have not reappeared in approx 3 hours of night driving where they would appear within 15 minutes previously.

I will now try and work out how apparently perfectly operational motors can cause the spurious warnings experienced. I suspect electrical noise is being fed back into the lighting circuits from the motor commutators.

Thanks again Guys. I know my car far better now than I did 3 weeks ago.

Hi Reidal,

definitely it's some electrical noise that did it!!

Just yesterday I changed my alternator, and..... the stupid false alarm still exist..... My last theory is that the alternator (or the voltage regulator to be precise) cannot maintain the minimum voltage level or cannot produce smooth direct current. However, it's wrong.

I will try to disconnect both headlight levelling motors, and lets see how it works. Anyway, I just beginning to think the aux fan motors is the most probably culprit because it's the only motor consuming the most current. I will try to cut off the aux fan while driving at night (hope it will not turn the stupid false alarm on).


Eri.

[Unregistered]

Hi i have a UK E34 520i (01/93) with a wierd problem!

I have no drivers side sidelight, taillight or number plate light.

I've checked all the fuses and connections, and then went hunting for the LKM, which I cannot find! i've checked the fused box carefully with the pictures off E34.net but it' looks nothing like!#

Help, please before I end up getting spoken to by the nice policemen

[lotus88]

Hi i have a UK E34 520i (01/93) with a wierd problem!

I have no drivers side sidelight, taillight or number plate light.

I've checked all the fuses and connections, and then went hunting for the LKM, which I cannot find! i've checked the fused box carefully with the pictures off E34.net but it' looks nothing like!#

Help, please before I end up getting spoken to by the nice policemen

Hi there, I have the same problem, if you find out where the LKM is can you let me know too as I want to tackle mine this evening

[Unregistered]

Hi Lotus88,

Yes I will, I hold out no great hope though!

'local dealer is as helpful as mud, and Haynes make NO!! manual for these cars!!!-Unreal'

Bob1004

[lotus88]

Hi Lotus88,

Yes I will, I hold out no great hope though!

'local dealer is as helpful as mud, and Haynes make NO!! manual for these cars!!!-Unreal'

Bob1004

Hi Bob, Haynes do make a manual that covers both the 3 and 5 series cars but it is really a complete waste of time. You can download it for free froma Russian web site. It lloks like we have the same problem with intermittant low beam, I am going to take my LKM out tonight if I can finf it and solder it up. I will let you know how I get on.

Peter

[Unregistered]

Hi Lotus,

Yes, I bought the manual for the 3/5 series after speaking to haynes on the phone...took it outside halfords, read it, took it back!

If you do have any luck in finding the bloody thing let me know...I also tried the 'stomp' test today and found that it doesn't work either... ;-(

bob