hi i changed the battery but the light on the dashboard is still on .

Owner: No one can answer your question without testing your vehicle. Some of the European Vehicles require a setting change with a Capable Scan Tool when a battery is replaced, in order for the charging system to manage a new battery, which requires a different strategy than an old battery. This MAY or MAY NOT be the solution for your warning lamp " on " condition. Your Mercedes is a high-end vehicle, and therefore it requires high-end diagnostics. See a Professional !