Water in the boot.
Just an observation really, but it could save people a bit of cash.My Mrs had the sat nav screen and indicator lights on the dash conk out, the indicators were working. In the boot, under the cd player on my 2002 X5 is a well which had about 4" of water in that seemed to be shorting out a lot of electrics. I cleaned out the plug and pulled out the grommet to drain out the water, replaced them and then left a hairdryer in there to dry it out. seems to have sorted it out. So I would suggest that its definitely worth a look.