If the battery should die on your Mercedes-Benz, the airbag light on the instrument panel may stay on after you hook up a new battery. The oil light indicator also may stay on, and the radio may not work until you reset its code. You can reset the airbag and oil lights with a service-light reset tool available at most auto parts stores for about £16 to £26. To reset the radio, you will need the code included with the paperwork from the car dealer.
Insert the reset tool into the Mercedes' data-link connector, which is near the bonnet-release latch. Turn on the ignition.
Press the tool's scroll button until "Mercedes" appears on the screen. Press "OK."
Press the scroll button until the model of your Mercedes appears. Press "OK."
Press the scroll button until "Reset of Airbag" appears. Press "OK."
Press the scroll button until "Reset of Oil Service Light" appears. Press "OK."
Check that the lights are off and disconnect the reset tool.
Turn on the radio and enter the radio code using the buttons on the radio. If you don't have the code, you can get it from a Mercedes dealer or mechanic. Tune in a couple of stations to make sure the radio works.