Originally Posted by Sarge
Apparently the sunroof drain, although I'm not sure how; I removed the caps at the end of the lines so the line is free-flowing without the little grommet 'drain' valve, as people advise. Somehow it still filled with water. It came in through the battery side (tray above battery was full of water, as well as the tire compartment (enough to submerge the electronics).
Anyone have any idea on the electronics?
In most cases like this, those electronics need replacing. I would try to find used modules from a junk yard, online etc. Possibly open them up to dry? But if they had power when it happened, probably bad.
The previous owner of our 08 had the exact issue, $4873 on the repair invoice for module replacement. They managed to get the BMW dealer to take it on trade towards a new 5. We bought the car and immediately relocated the modules away from the spare tire area.