E38 Rear Indicator Won't Turn Off

[akanatural 0]

Hi guys ... i just returned from Australia to find my '97 728i having a couple of issues.

The worst is my Right Hand Rear Indicator Light stays on.. even with the car off.

I have to disconnect a battery terminal to make it go out.

The worst thing is i have a month to get it registered and i took it for a warrant todayand after mucking around with a wire harness for a bit they ran outta time to sort it.. so it failed its warrant.

Does anyone have any idea what it could be ... they seem to think its a wire harness and want a crack at it on Monday ... but im not so sure ... could be a bunch of things really but i wanna try all avenues so any info would be great ..

Cheers!

Edited September 28, 2012 by akanatural

[jochen 4]

Hi guys ... i just returned from Australia to find my '97 728i having a couple of issues.

The worst is my Right Hand Rear Indicator Light stays on.. even with the car off.

I have to disconnect a battery terminal to make it go out.

The worst thing is i have a month to get it registered and i took it for a warrant todayand after mucking around with a wire harness for a bit they ran outta time to sort it.. so it failed its warrant.

Does anyone have any idea what it could be ... they seem to think its a wire harness and want a crack at it on Monday ... but im not so sure ... could be a bunch of things really but i wanna try all avenues so any info would be great ..

If no-one has rewired any of the taillights then the cause can ONLY be a faulty LCM

If you have the ignition OFF and the light switch OFF then all lamps must also be OFF.

If a lamp stays on, it is getting power from somewhere, and the most likely fault is that the transistor on the output stage of the LCM that supplies that lamp, has failed.

If you have an electronics experience, you can diagnose and replace the transistor easily.

Otherwise, replace the LCM

CAUTION:

Coding of the new LCM to your vehicle is crucial!

The odometer and vehicle coding are stored in the LCM, fit one from another car, without coding to your vehicle and the odometer tamper light will come on, and the coding will likely be incorrect.

Coding of the replacement LCM to your car can only be done by original BMW software (or equivalent expert tools)

[akanatural 0]

Thanks Jochim, yeah its weird that one bulb should stay on.

My local mechanic who did the WOF check unhooked the bulb and meter checked the power and it was a constant just to that bulb - all the other bulbs - reverse lights, indicators etc worked as normal.

I got this suggestion on the bimmerforum:

"Try to disconnect the battery for 15 to 20 minutes. While it is disconnected push the flashers a couple times to make sure all the spare charges are expended from the car and then hook the battery back up. Things should be ok afterwards for you then."

Im not sure what that would do but i'll try it when i get home tomorrow.

I'll probably take the car to a local BMW / Euro specialiat on Monday / Tuesday and ask about a new LCM.