The warning module is for the seat belt system, but it has diode in it that can burn out in weird ways and allow power to run in the opposite direciton. This causes a problem. Hint, open the door and push the door switch with your hand and see if the window works.
ASE CERTIFIED MASTER AUTO TECHNICIAN
LEAD TECHNICIAN FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM