Problem Resolved....You'll never guess
Or you might. I have had more things "broken" by the dealer than I have had actual car failures.
I had my S420 in the dealer about two weeks ago for a brake light switch replacement and apparently they knocked the evap. drain hose out of its hole in the body so it was draining directly into the cabin. It took so long to discover the water because the under carpet pad in this car is 8" thick in most areas.
Anyhow, I pulled all the carpet out and repaired the problem.
Very dissapointed with Mercedes service....Once again.