See also:

Making adjustments in 5 mph (Canada: 10 km/h) increments
Briefly press the cruise control lever beyond the pressure point, up 1 for a higher speed or down 2 for a lower speed. The last speed stored is increased or reduced. ...

Adjusting the backrest angle (2nd rowof seats)
WARNING   The seat belt only offers its intended protection when the seat backrest is in a nearly vertical position and the occupant is sitting upright. The seat backrest and seat belt ...

Roadside Assistance button
  Press and hold Roadside Assistance button 1 for more than two seconds. This initiates a call to the Mercedes-Benz Customer Assistance Center. The indicator lamp in Roadside Assistance but ...