Very strange:

The security guard in my building recently purchased an '82 380 SEL. Car started and cranked fine.
He complained thathis left-side window switches were reversed. Having some experience with this, I removed the console cover and did the reversal in 2 minutes. Fine.

However, when we turned the key, the starter cranks fine - but the engine won't turn over. Seems like something electrical, but simple.
Could it be some sort of built-in security item, that doesn't allow the car to start if it has been turned on and off too many times in succession? Do we need to wait a while?

Or can it be a fues, like to the fuel pump?

Strange!! Can you help?

I have replaced many of the fuel pump relays on these cars. It is located in the fuse box to the rear. Tap on it and see if the car will start.

__________________
Benzmac:
Donnie Drummonds
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 11 YRS