If it is the same as my 500SEL, it will be the control for the rear retractable window blind. I managed to get my handbook from my local dealer who had to order it for me from Germany I think and it took about 4 weeks to arrive. If you really get stuck, let me know and I can order one for you from here, cost me about $20, I think. This is the owner's handbook that lives in the glovebox right ?
