Verified answer

First remove the radio from the dashboard.

Then post the radio make+model plus all the letters+numbers on any labels,barcodes or stamped in the metal casing.

This information can then be used to see if a code can be calculated

Sprinter Radio Code

For a key or code for the radio, I had to prove ownership to the dealership.

The radio code was given to me over the phone once they had a record (proof) that I owned the car.

The screen should not be blank. Even if the radio is asking for the theft code, the display should read 'code'. Is there power to the radio?

you need the serial number of the radio, its at the back of the radio ,get the serial number and put it in this decoder it will give you the code.(choose mercedes decoder). https://sites.google.com/site/autobestanswer/radio...

Or maybe you swiped one? If that's the case you should Google it.