The overly complex turn signal/high bean/wiper control arm is not very reliable and could definitely be your problem.
I installed a new unit on my old W123 300TD to cure a high beam problem. Easy to do, just open the underdash cover on the drivers side and you should be able to do it.
An service mananger once told me that one of problems with this unit is that is too long, and drivers tend to hit when they get in their cars.
CL 500, 1998
S 500 L, 1998
E 320 T, 1995