If anyone owns a BMW 5 Series E39 model they may have this fault. A fault in the headlights tends to appear somewhere within the model years of 1998 and 1999. It seems to be a problem with the offside main beam headlight permanently staying on whether you have the ignition on or off and the headlight switch in the totally off position.
When this fault happened to me, I had the lights on for a short while and when I pulled up and went to switch the lights off again I found the main beam just would not go off. I went into the house where I had to go and do a job, but when I returned to the car about 10 minutes later the battery was already flat. After calling the breakdown service out, the man restarted the car and after much tutting just said “yeah well its a BM mate it could be anything but its probably just a relay or something that’s stuck on”. As a quick measure I took the bulb out to get me home and mulled over the puzzle all night.
The next morning I decided it had to be a relay that was at fault so I hunted around the car looking for relays for the lights. I checked the handbook for the location of it. I took panels off here and there,I removed literally every fuse and relay I could find, pulled them all out and put them back in again. And guess what the light would still not go off. So I started looking on the web for answers. I visited most of the BMW forums I could find and found a few owners that seemed to have the same problem. Some of the answers that came back were quite similar, some people said it had to be a relay, someone suggested removing the battery for 10 minutes, then reconnecting it again and it should all reset itself again and everything should be Ok. I tried the battery idea but that didn’t work either. So over the next week or so I went back to the web again and finally someone said they had tried those things and then eventually gave up and took their car to a BMW dealer.After parting with a wad of cash to pay BMW for their services, BMW said there are no relays to control the lights and the lights are all controlled by the “LCM”.
Now the “LCM” is the light control module that controls all the lights. If this LCM fails you just have to replace it. Simple! Apart from the LCM is only a BMW main dealer part, and the cost, over £200. At that time £200 was not quite an option for my pocket, so I drove around the next few months with the bulb still disconnected. Then MOT day started to loom and there was still no pocket money to buy the LCM. So I rang my cousin in desperation to ask if he had any ideas of how to get the car through the MOT?
He said to me “why don’t you cut the positive wire from the offending light, then run a new wire from the other light that’s working to it so they both run off the same supply. What a good idea! So I did exactly what he suggested. The car sailed through the MOT and another further 6 months down the line it is still working to this day. Which is just as well because the £200 is still not there.