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Discussion Starter · #1 · (Edited)
I just bought a nice used 525i last weekend and it drives nice and is in good overall condition, less a few city dings. It has 140K on the clock. I am still getting used to the car and thought maybe I had left some switch on or something like that.. I have been driving an old 89 honda no power anything lol....

Problem I am having is the battery seems to drain down overnight to the point where everything was working but the car would not turn over or start. Went and got my other car and it started right away with a jump.

I then drove it to work (30 miles on freeway) in sport mode to get some juice back into the battery. this seemed to work as I had no problem starting it later when I got off to go home (8 hrs l8tr)

This morning I had the same problem. jumped again and drove to work. Car running fine. I put a multi-meter on the batt and check the output voltage and it seemed good (12.7 volts) @ idle/ / 13.7 @ 2500rpm. I then turned eveything on I could headlinghts, A/C, hazerds etc... and with all that, still had good voltage(i think) @ 2500prm (12.9)

There was a "license plate lamp" error on the dash but had thought the bulb/s were out and had planned to go get some replacements today..

I checked the indicator "dot" on the (OE) battery and it was black (insuffeciantly charged?) green=good/ black= so-so// yellow= replace

While in the process of doing all this and putting a trickle charger on the batt, my co-worker noticed the license plate lamps were on while the headlights were in the off position. I am thinking this is the cause of the drain on the batt? Could this be a grounding issue w/ the harness in the trunk? Is this something that happens with this model with some age?

I also noticeed that the High beam switch does not want to stay switched "on" you can flash but thats it...

Not sure if the 2 are connected but I will also look at getting the H.Beam switch working as well... any advise with this would be great..

I pulled the License p lamp bulbs in hopes of stopping the drain and get the batt back up to snuff. :dunno:

I am happy to be in a BMW again. I used to have a 1973 2002 and loved that little car...

Thanks!!
 

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The high beam switch probably has nothing to do with the plate lights. The harness at the trunk hinge does go bad and can cause many issues. I dont think you should have power to the plate lights with the switch off. The LKM light kontrol module could be causing this.
 

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The high beam switch probably has nothing to do with the plate lights. The harness at the trunk hinge does go bad and can cause many issues. I dont think you should have power to the plate lights with the switch off. The LKM light kontrol module could be causing this.

http://shark.armchair.mb.ca/~dave/BMW/e34
 

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license plate lamps were on while the headlights were in the off position.
Affirm that you have your radio code. Disconnect battery. Unravel the harness/tape at the left hinge and work your way into the trunk. IIRC, you should see a brown or brown and white ground wire abraded in half. Report back. Any broken wire found in the harness ought to be fixed, of course..
Colin
 

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Discussion Starter · #5 ·
Thanks for the replies// update

Got home last night and figured it would be a good idea to check continuity over the fuses since they all looked original (yikes)! #12 was blown (mirror adj circuit) and the rest looked OK (intact but old) but I'm going to replace them all with new ones...

I will check the trunk harness today on my lunch break. The car started fine this morning so I think I'm on the right track. Will report later..

Thanks!
 

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the dash headlight swich has three contacts.

left side park, rightside park, and dash + license lights.
that leads me to blame the lkm. otherwise dash lights would be on too.
 

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Discussion Starter · #7 ·
Update...

Well,

I started to pull everything apart to trace the harness into the trunk and ran into a blockade about getting the radio code from the dealer.

Not really haveing the time to deal with all this, I just caved in and took it to my local (close to work) indie German auto shop- San Carlos German Auto works.

Turns out, there were 6 wires in total that were abraided and needed replacing. So they did that, tested the batt (fine) charging system (fine), Draw test (fine) and the tail lamps are now not on, when the headlight switch is off...

I did see some info about the KLM unit and will keep this in mind if the problem persists.. but it looks good for now. :thumbup:

Thanks guys for all your suggestions, this forum has a ton of great info.

Hopfully the repairs are behind me and I can start working on upgrades! :bigpimp:

Nick~
 
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