its a common problem with these cars
usually happens when people have their windows tinted
the water drips down to the left side of the trunk... where a bunch of electronics are located.
check there for dampness
'03 745i - modded - GONE -
'08 535i - Sport - Sport Trans - Navi - Comfort Seats - daily beater -
'07 GSXR-750 - Gray/Black - Akrapovic Ti Shorty Exhaust -