Just got off phone with service rep; they slit the harness cover and peeled it back, and checked several spots, the service rep indicates that the wire harness looks like new(maybe the PO had it replaced?). No evidence of heating or any other type of insulation breakdown. At this point everything seems to point to a faulty throttle actuator on the driver's side. Apparently, the service rep has some connections and may have a line on a used throttle actuator that will do the job... tomorrow will tell.
Mike, thanx for the post with the part numbers, I have them saved for possible future use.
A mercedes is an inanimate object and therefore must respond to logic and reason.