Help needed battery empty in 2 days.

perhaps the light in your car boot works canstantly ?!

Hi Bertil,

first of all here are the ETMs by built year, go to your built year and see what is connected to fuse 20
http://shark.armchair.mb.ca/~dave/BMW/e34/

finding the power drain - for beginners, but you know that probably

If you are a beginner in electric issues, this walks you through it, hopefully:

I'll try to make it simple, ...

The meter should have an A scale (Ampere) for reading current. Preferably, a High amp one (10A for example). In some of them, this high amp scale requires the red plug of the wire probes to be connected in a different hole. We do not know the magnitude of the current involved, so in order to preserve the meter, it is better to start reading in this high amp scale.

Disconnect the ground (negative) lead to the battery (electronic devices in the car will loose status when battery is unplugged, so you will need radio code for example), connect the positive (Red) meter probe to the negative thick wire to the battery, and connect the negative (Black) probe of the meter to the negative battery post. Be sure that the probes are inserted in the proper holes in the meter for the readings (Amp) you intend to take.

If you have a leak as you assumed before, you should have a significant reading in the meter (maybe/sometimes more than 50 milli amps, > 0.05 Amp). If the selected scale do not allow you to have a clear reading of the leaking current and you want to change down scales, do so. Remember that some meters require to select a new hole in the meter for the red probe in order to select a lower Amp (Current) scale.

Once your meter is properly set and you have a good steady reading of the leaking current, proceed to remove, one by one, the fuses on the fuse box. Keep an eye to the meter in order to identify which fuse removal is dropping down the current in the meter. The leaky circuit is feed by that fuse.

Investigate what devices are associated to that fuse, plug the fuse back, and start disconnecting all devices one by one until you get again a reading drop. That device would be the culprit.

But in case of our E34 the complete electronics come to a rest/sleep modus after about 16 minutes. That means that you should not open the door again for example but keep it locked for checking. Therefore open the rear windows and the hood, remove rear seat and then lock the doors and wait 16 minutes. Then you have access to the battery and the fuses thru the rear windows.
If the door is unlocked, the GM is again on stand-by modus and maybe others.
When all is 'sleeping' usual drain is 30-50 mA.

The wiring diagram for E34 cars are in above link.

I just checked, on page 25/556 fuse 20 covers
EML in case of 6-cylinders
page 26
instrument cluster/check control
multi-function clock
page 27
park ventilation with IHKR/F3
integrated climate regulation with filter
OBC

If you ask me, I would go for the last 3 items first to check.