Fuel filler flap
The fuel filler flap is unlocked or locked automatically when you open or close the vehicle with the SmartKey or using KEYLESSGO.
The position of the fuel filler cap is displayed
in the instrument cluster 
. The
arrow
next to the filling pump indicates the side of
the vehicle.
Example: Sedan
1. To open the fuel filler flap
2. To insert the fuel filler cap
3. Tire pressure table
4. Fuel type
See also:
Mercedes-Benz M-Class Owners Manual
...
Fuse box on the left in the direction of
travel
Open the hood.
Remove any existing moisture from the
fuse box using a dry cloth.
AMG vehicles: remove the control unit
above the fuse box.
To open: undo screws 1 with an Allen
key.
...
Important notes
In order to prevent the vehicle's battery from
discharging, the interior lighting functions are
automatically deactivated after some time
except for when the SmartKey is in position
2 in the i ...