Beware the Service Advisor
Larry is right - the wiring harness problem on these cars is common. Seems MB would rather fight the customer than make a recall.
One word of warning - if this is an MB dealer, you should know that their much vaunted Service Advisors may be working on commission. A guy who use to be one told me this - can anyone else confirm this?
If so, that may explain why so much unnecessary work is done. It pays to get a second opinion from an independent who specializes in MBs.