Just wanted to post the solution to my ESP/ABS/BAS problem.

After trying the brake light switch to no avail, I had the codes scanned at a local indy shop and the lateral acceleration sensor had thrown a code. This module is part of the ESP system and is located under the carpet beneath the driver's seat. Believe it or not Mercedes wants > $2K for this module! I found it on a German used parts website for < 50 Euros I finally got it replaced today and the annoying beeps and lights are gone

It's MB part number 000 542 65 18.

good luck!