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

[Reidal]

Hi All

New boy on the block. I have been through the forum but can not find any additional info so here goes hoping someone can help.

1993 E34 530i RHD 191k km's. Warning display for Brake, tail, number plate and dip light comes on when I switch on the head lights and won't go away until I switch the lights off then turn ignition off (short delay before the warnings shut down). No warning during the day (lights off of course).

I have read the info re the LKM and as an experienced electronics tech I can confirm I have re soldered all the relays (4 relay LKM) and LKM connector joints. I have also re soldered a number of through board holes and components (using hot air gun).

Absolutely no change. Problem persists. All the lights work correctly at all times.

Does anyone have any idea's?

[winfred]

theres a good chance the check control module (ccm) is dieing, on usa cars it's next to the lkm in the fuse box, someone here on the forum figured out how to test and repair them

[Reidal]

Thanks for the help Winfred.

I have searched for and found the CCM information and will give it a look tonight.

I'll confirm how thing go.

[Phil Sanderson]

Check the wiring on the left trunk lid hinge arm for broken and touching wires

[black_bird_blue]

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

[Reidal]

All good input thanks guys.

I have checked the CCM carefully and can find no circuit board fractures and all the components appear to be OK. Some solder joints looked iffy but checked out electrically OK (re-soldered anyway just in case).

Moving on to the trunk (We Aussies call it the boot by the way) hinge wiring this weekend and will also check out the headlight leveling motor while I'm at it.

I must say it is fun to be tinkering again after many years in Japanese clones (although I might feel differently when I have a major melt down).

Also ordered a Bentley on Amazon ($83 USD opposed to $200 AUD locally)today, so I will be able to go in depth if this week end is unsuccessful.

[Unregistered]

Hi...

Mine is also a RHD 530iA '96 and I also experience exactly the same symptoms as yours.

BTW, I've gone most of the forums suggested, such as making sure the bulbs are of the high quality brands and they are of the same types, and checking the wires on the left side of trunk door. Furthermore, these are few more things I did :

1. Add ground cables from each of rear lamps (including reverse light and licence plate ligths). The new ground cables go directly to the (-) of the battery. I suppose the problems was due to bad grounding.... IT WASN'T... Helps a bit.

2. Change both LKM and CCM. I swapped with the same car (530iA) with the same year. My old LKM and CCM don't do any trouble in the new car. But the nasty false alarm still ding in my car..

3. Resoldered LKM. Furthermore I added reverse polarity diodes to the primary side of each relay (in case there is wild reverse current). Helps a bit, but not solve problem.

4. Putting reverse polarity diodes onto the troubled lights (lic. plate, tail, brake and low headlights) to fight wild reverse current. Still not solved.

5. Maybe I am going to put some high capacity capacitors such as used in the high powered sound amplifiers, because I am still believe that the problem is bad connection somewhere, and the only place I haven't looked at is the power (pin 2 on the LKM).


I am very curious to solve this problem. At least I am 'happy' to find someone with exactly same problem. Even the stealer hands up about this.



Eri.
530iA '96
53000 km overall.

[Phil Sanderson]

On my car, for some unknown reason, the wiring loom was cut where it passed through the metal wall behind the back seat to underneath the back seat. It was my reversing lights that were intermitently coming on then off. With to boot/trunk lid closed the lights worked but when I opened it it tugged on the wiring loom and split the reversing light wire under the back seat. I know this sounds odd because the wiring loom is attached at the hinge and in other places, but it can still move. My car is an '89 525i - on cars with battery under seat, the wiring loom will come through right behind the battery - I suppose.

Phil

[Ian W]

I have a 94 rhd 530, that does the same. The symptoms may be slightly different as brake, number plate, dip, warnings only come on when I have the lights on and apply the footbrake for any length of time.

When I got the car it annoyed me so I changed all the bulbs to bmw which did increase the time it took for the warning to come on.

I presumed this was just the brake switch , but I've never got round to replacing it.

Glad I've got used to it, if it turns out tricky to fix.

Good Luck

[Gary M]

You might to want to check and clean the contacts where the bulbs plug into the lamp assemblies. They corrode over time and sometimes cause problems. Although I don't know if it would be the same type of problem you're experiencing.