Andy_M

I have a '90 300E that keeps blowing fuse #3 which is for the dash lights, controls lights, right side parking lights, and headlight wiper motors. The first time it blew was at night about 1/2 way between work and home. I replaced the 8amp fuse and it was ok for a couple of days before it blew again. Once again at night on the way home. Since then, when I replace the fuse, it blows as soon as the parking lights are turned on. When it blows I lose dash and console lights, right side parking lights, and the door buzzer.

The wiring diagram would seem to indicate this is most likely one of three things: 1) Light switch; 2) Headlight wiper relay; 3) lighting control relay (the $180 baby). The problem is that I can't find a listing anywhere for a "headlight wiper relay" so I don't know if this is actually the interior light relay (which apparently works fine) or the

I'm thinking it is most likely the light switch. Opinions ? Other ideas ?

ZedStyle

just pull out the 'headlight wiper relay' and see if that helps

ps2cho

http://mercedesshop.com/shopforum/sh...d.php?t=240897

Try pulling this one apart and check for cracks.

Andy_M

Thanks guys. Looking at the wiring diagrams, it looked like the most probable place for the short was inside the light switch. Three of the four feeds that flow through the #3 fuse are connected to the light switch. I ordered a new switch and installed it and that eliminated the issues.