Wow thank you so much, this thread saved me a lot of needless work, I was having a similar problem with my 1995 E300d not turning over. It really seemed odd, we could not even jump it with another car, The battery voltage would drop when we turn the key, to 11v, but nothing from the starter. I also noticed the gauges were not working but did not think anything about it. Just about ready to remove the starter, then I read post 7 of this thread above and guess what my fuse # 5 was intermittently opening, changed it and problem solved.
Thanks again