1986 190e mb Why does my headlights turn on my wiper

I have a weird thing that just started happening with my 1986 Mercedes 190e, when I turn the headlights on my wiper automatically turns on. If I don’t turn on the headlights the wiper and all its functions work normally. What is causing this ?

Are the wipers also turning on the dash lights?

There may be a a grounding problem with the headlights causing this.

Did that model have auto wipers? You know the ones that sensed rain and turned them on for you. I seem to remember that was about the time that silly thing came out. It may be failing.

No just the wiper. I have noticed that my passenger side headlight seems dimmer when this happens

I think it is a ground issue but I don’t know where to start to fix it. any ideas ?