I did a search on adjusting the neutral start switch but there's nothing more specific than "adjust until the car starts."

Is there a more scientific process? My 81 SD has 4 pins in the connector. Can someone describe which make contact or lose contact when the selector is in Park or Neutral?

Better still, are there better key words than neutral, start and adjust?

Thanks,
Sixto
91 300SE
81 300SD