'94 E320 electrical problems - solved
 

My E320 Wagon has 181500 miles on the clock. Everything works except for this:

The electric mirrors doesn't work (neither right nor left, but the heating on the right side works).
Seat belt warning system doesn't light up.
Everything else works (power seats, heated seats, power windows, power moon roof etc).

Edit 18. April: I can also add that when I open the rear doors, the dome light doesn't light up. It's okay when I open the front doors. There's also a button in the dashboard for interior lights, but this is out of order. When I press it, the lights in the luggage compartment doesn't light up.

Anyone got any clues to what could be causing this?

Except for the seat belt warning system, these faults were all faulty switches... :)