Thanks for the reply Norm, I was able to remove the black connector after turning the white part 1/4 turn clockwise (one would never guess!). It seems to me due to the very tight space, you'd need to drop the transmission to remove that switch? In any event, the wiring looks pretty good still (the car only has 50k miles on it), so I just sprayed some contact cleaner on both sides and put it back together. Turning the white ring back took a bit of leverage with a screwdriver, but everything is back in place now.

Did it work? Did you get the car to start.?

Oh, my vehicle had 70,000 miles and the wire harness was completly bad.

No, shouldn't have to - it's just very tight. It helps greatly to work with quarter inch drive sockets and maybe a swivel head rachet. There is an alignment trick to putting it back in. You have to use an alignment pin of a certain diameter, something like a drill bit, to ensure that it will work properly. It helps to have the MB CD or some other write-up. Poor alignment may actually be your problem.