I've had problems with a stuck button on a key fob causing random tailgate open and alarm.

Historically the # 1 cause of drained battery is the FSU aka FSR.

You can measure the resting voltage after resting overnight to see what values before and after. It's much easier than training down current drains.

To do that I have a magic tool you plug into a fuse spot and it measures the current found through that fuse (which is temporarily put into the tool)

The FSU is the cause maybe 60-80% of the time and takes 5-10 minutes to pull it out. If you take it out and no overnight drain then put it in and have drain problem solved.

Do you lock your car at night? If locked the tailgate will be disabled, if unlocked or won't be allowing for a malfunction to draw power

__________________
2011 E70 • N55 (me)
2012 E70 • N63 (wife)