2005, e320, CDI, 135k

Won’t crank and start sometimes. Usually cranks and starts on a second try, or a third, so far. Sometimes helps if I turn all the way off then try again. Got a little buzz yesterday for a half second, next time she started.
All the systems turn on. Thinking of spraying electronic cleaner into key hole then maybe lubricant? It’s the lubricant I’m not sure about. Haven’t tried moving the steering wheel yet. Later today though.

Are you saying that the starter will not engage? If so, could be the neutral safety switch.

However if you can move the shifter and find a sweet spot for the starter to engage, this is a sign of worn out shifter bushings.

At least on my '81 300SD. Assume yours is similar.