Seat control module failure. 2 modules per car, 1 for passenger seat, and 1 for driver seat fail. the defective seat control module unit will deplete the cars battery overnight resulting in a no-start condition the following day. a new battery, or a jump start, will get the car going again. the common immediate resolution is to unplug the seat control module which would impact the seats ability to respond in an accident. the replacement part and diagnosis from mb dealer is approx $700/ module. this is a huge liability for mercedes owners and the repair should be investigated for seat function safety. i understand the part number has been updated, which i believe is an admission by mercedes that the original part is defective. *tr