I have a problem with my 2002 A160 (W198), when the headlights are on and I either use the indicators, the wipers or washers then main beam comes on. It does not happen if the headlights are off, nor when the front fogs are on. Any ideas please?

 

The indicator stalk has a pivot pin holding it in a housing. The mounting points have broken allowing the stalk to move out of alignment slightly - this causes the problem you describe. I have attempted a repair without much success. The only real option is to get a new unit.