Does anyone have a clue what is causing this. I just picked up my car AGAIN this morning from the dealer. I had 2 minor things that needed to be taken care of, one they totally screwed it up, the second I had to prove there was a problem and have decided NOW that I can live with it and refuse to take it back. After leaving the dealer I heard this distinct HUM coming from somewhere in the rear of the car. It wasn't any louder with the window open or with change of car speed or engine speed or in drive or park. I checked the rear seat area and it almost seems as if it is coming from under the rear seat area, but I can't be sure. I really don't want to take the car back to the dealer because they have already scratched the nice chrome on the door jam replacing the seat belt on passenger side and totally screwing up the auto-glide forward mechanism and internal latch. I brought a car in perfect condition to them and they are screwing my car up with only 2700 miles on it.

Does anyone know what the hum noise may be? Thanks.

This is my last Mercedes for sure. Great cars, but damn dealers are worthless and cause more problems.