I had the same problem in my 560SEL, it is indeed a fuse (can't remember which), you may still have a short. In my car, the little light under the door that goes on when the doors open had become loose over time. One day when I closed the door, the light had fallen so far down that it got smashed, causing the wires to touch. It took me a while to find it, since you don't really notice these lights in the daytime. Hope this helps...