I have a 1982 300SD. Odometer stopped at around 270K. All glow plugs are new/working, new battery, new fuses, clean fuse box, new shift lever and trans lever bushings.

After replacing the neutral safety switch yesterday (genuine Mercedes NSS) my car will not start in P or N. I don't think that I have parking lights.

I have gotten the car started (I had been starting the vehicle by using a length of copper wire, bridging two wire terminals in a black box located on the passenger side, above the wheel well) and after turning off the engine, I was able to restart the car, once, using the key (in both P and N) but only once. I couldn't restart using the key after that.

After I first installed the new NSS, and couldn't get the car to start, I used the copper wire to start the vehicle and there was a sound that I hadn't heard before, and haven't heard after when using this method. It was kind of a quick, scraping sound. It almost reminded me of when I have sat in a gas car (quiet engine) and turned the key, not realizing that the car was already on, and it makes an unpleasant sound.

I installed the NSS exactly as it came out - white plastic collar rotated up, pulled out the wire plug, unbolted the NSS. New NSS in, wire plug in, white collar rotated down.

I did this on the streets of Queens, NY. I use the vehicle regularly, it's not garaged.

Does anyone have any idea of what the problem may be?