Battery drain problem 86 535i

[R-Tru-D2]

Just picked up a 1986 535i that is draining the battery when the car is parked for more than a day or 2. I've verified that the battery has adequate charge before being parked, but will just drain down to nothing in a matter of 48 hours or so.

Some things I've noticed:

1. On occasion, the seat belt chime will continue to chime when the car is off. Not always - but sometimes

2. Electrical seat adjustments are operational when the car is off. Not sure if that's normal.

3. OBC flashes with dashes and "UHR" on the display - even when car is off. Again, I'm not sure if that's normal.

I'm not an electrical expert, but I do have a Volt-Ohm meter. Not sure where to start testing, and how. Thinking of just removing fuses 1 by 1, and testing for current at the fuse with the car off. Would this be a good way to hunt down the source of the drain? Other suggestions? I'm actually in the process of trying to sell this car when I discovered the drainage problem.

[BimmerGurl]

Well this sounds alot like what happened to me. It seemed like after a few days when I went to start my car the battery would die almost immediately. So I went and bought a new battery thinking that it would slove the problem, we'll it did for awhile but then it started up again, so then I had to think that maybe something was being left on without me knowing it and I began to notice that when I went to turn my fog lights it would take a bump on the road to make them come on and so I figure that the fog light relay was draining my battery so I pulled it and the problem has stopped it has been over 3 months with a perfect start everytime, it just sucks that i had to buy a new battery before I figured it out! So maybe thats your problem...I guess all you can do is start testing and hopefully it wont take long for you to find the problem....wish I could help you more! good luck

[jeffreyb4me]

The most likely cause is the "Unloader" or "Relief" relay with is mounted and I.D.'d under the fuse box cover. These can 'stick' intermitantly powering various consumers after the key is off.

Your seats SHOULD be movable with the key off.