Took my 2006 X3 (Mk4 Nav unit) in for an ongoing door leak problem. Told me it was actually the sunroof drains. They fix it and next day pick up the car and the Nav screen is down (I ALWAYS leave it on, so it normally pops up upon car start). Nav worked fine when I brought it in, now dead, and naturally the Dealer says "tough luck, not our fault. Nothing we did on the leak would affect the Nav"

After a day it came back on briefly for about two starts, then stopped again for good. After reading some forums that recommended pulling the battery for 15 min., I tried unplugging the Nav unit itself in the trunk (blue plug). If I do that and plug back it, the unit will boot itself and work fine, maybe for 1 or 2 starts again, sometimes not. Seems to be some sort of I-buss wake on start problem? Would this still be in the Nav unit itself, or could something else on the I-buss cause this? Do I need to actually pull the battery or will the plug do the same thing (as in maybe the entire I-buss needs reset)?

Then my leak started again, went back to the dealer and talked with the service manager and apparently when it leaked before they had found some water in the bottom of the battery well!!!? I asked about them pulling the battery and frying the unti, but he said they just vacuumed out the water. Riiiiight! I say that's where the frying occurred, but no way to really prove it. Service manager naturally wanted to charge $4,000 to replace everything!

In the midst of all this, I also was able to update the firmware to V32 (4-1/60 to 4-1/100) in hopes of somehow fixing the Wake up problem, but didn't help.