It may sound obvious, but check the fuses carefully.

Had the same problem with my E320T (except for the low beam lights) and it turned out to be an "almost" burnt fuse. At first glance it looked O.K., but decided to change it anyway. Afterwards, the problem was solved.

A very small gap (not visible to the eye) in the fuse wire will trigger a problem.

A. Rosich
S320, 1998
E320T, 1995