Good news but try Don Jackson next time they are A+ in my book.
Is this new electrical problem something that developed after they fixed the O ring in the oil filter cover?

 

No, I noticed the signals stopped working on the way to drop it off to resolve the issue. When I went to pick it up, I had no locking system, no power windows, no power moonroof, no interior lighting AND no signals.

Left it there, driving the dealer's 2011 E350. Nice ride.