Hello, I installed piaa fog lights. I like them, they fit in the bumper steps on my 2003 cargo camper. The piaa switch fit well in the stock location next to the headlight adjuster with a little sanding to the switch housing. With the ignition on the switch light is green, with the lights off. When I switch the lights on, the switch light turns red. It works fine but I dislike seeing a red light near the dash. I purchased a mercedes fog light switch to repace it, part # A 006 545 5207. It has 4 pins in the back numbers 1, 3, 7, and 10. The piaa switch has three wires coming out of it, a ground, an ignition on positive going to it and the ignition on positive going from it to the piaa relay. Does anyone know which mercedes switch pins I should connect those wires to. Any help would be greatly appreciated. My best, Ron