I have a 1993 300d 2.5 turbo. I have a post about excssive smoking posted and still trying to track cause.

I noticed a three prong switch / sensor on the throttle linkage over the valve cover. Does anyone have a pic of this arrangement,? There is a bolt hole beside it with nothing there, just curious if any thing should be there for the switch / sensor to sense?

I checked the SM wiring diagrams and it appears to be the "control rod sensor" but not sure I'm reading the diagram correctly. What does the switch / sensor up there do?