Seemingly another Mercedes 380SL Problem Solved

Hi folks -- this issue involved the door locks, which would not close. Or the gas flap and trunk either. So I did a lot of reading on this matter.  The master door locking system is one powered by vacuum, with its source ultimately being manifold vacuum that is routed to a storage tank.  From there the line goes to a "Master Element Switch" in the drivers side door, and then on to the passenger door and the rear of the car. Since the major culprit is the "Master Element Switch" according to internet reports, I just ordered one of those, replaced it, and "bam," the locks work!

This is a Mercedes vacuum system diagram, but not the one for my car.  The point is that there are lines running all through the car, rubber connections that can be disconnected, and diaphragms that can go bad.  The only way to diagnosis this is with a vacuum pump and patience, and I have neither.