My wife owns a 1985 300D Turbo and has been having a rather maddening problem for a while. Intermittently, the car will just not crank. Hot or cold seems to make no difference. She will turn the key and there is no click or anything else. Dashboard lights and glowplug light comes on (so I assume the glow plugs are working OK) but the car won't even make an attempt to crank. Also, it seemed most times the car didn't crank, the steering wheel would not lock either. We replaced the ignition switch within the last year and this did not seem to make any difference. Just this week, we had the neutral safty switch replaced and that has also not seemed to make any difference. Also, with the safety switch, some bushings in the shift linkage were replaced. Car cranks fine when it cranks. Sometimes, but not so much any more, she could jiggle the shift lever and it would crank then. This doesn't seem to be helping much any more. We have been to two different Mercedes specialists about it and still have the problem.
I have looked at the various other threads and I think we have replaced everything that has been discussed in other threads (ignition switch and safety switch).
As you can imagine, my wife is getting very frustrated especially since she spent over an hour trying different things to get the car to start to come home from work the other day.
Any thoughts would be greatly appreciated.
Eric