PeachParts Mercedes-Benz Forum - 1986 300E window fuse keeps blowing

All I wanted to do was get the radio working.

Thats how it started. The radio in the 300E wasn't working so I popped the fuse box to see if the fuse was good. Thats when I noticed Fuse "H" was blown. No big deal, removed the blown white 8 amp fuse and inserted another one. Now the right front and left rear windows worked! I put those windows down with the rest of them now while I continued on with the radio problem.

My diagnosis brought me back to the fuse box again but I noticed the fuse I had put in earlier was now blown again. I went to get another white fuse but happened to glance at the fuse card. Fuse H is a 16 amp fuse! 'Oh boy am I dumb' I thought to myself since I just replaced it with what I had taken out without looking. Went and got a red 16 amp fuse and put it in, turned on the key and I hear "pop." New fuse had blown and now I'm thinking what what the hell? More so cause it's starting to sprinkle and the window was still down. Since I noticed earlier the window switch in the console didn't seem to work (I had put down the window with the one on the rear door) I removed the switch thinking it may be shorted inside. I put a new fuse in, checked operation of the right front window which was working great, and swapped that switch to the left rear spot and "pop" again.

Then it hit me. The wiring where it passes through the doors must be frayed and shorting out. Removed the door panel, took the B-pillar trim panel off and pulled the wiring back though to the inside of the car and split the insulation off, sure enough the wiring wasn't just frayed, but broken completly! It's beyond me how I was ever able to put the window down in the first place.

So for anyone having similar problems with your windows not working or blowing fuses or even your rear interior light (it shares the ground with the light in the door), check the wiring where it passes through into the door.