There was no way I could resist that!! I looked in my CD for info on this but got bogged down with all that electrical stuff. It sounds as if you have one of the following to me, a worn out flasher, a bad ground or lamp out or incorrect wattage. I don't think the wiper is on the same circuit but knowing MB, it could be. General knowledge here for sure, but replace the flasher first. It usually doesn't cost much (at least on other makes anyway).