Here are the directions to reset the radio on a 1998 Mercedes C320:
1. Turn off the ignition.
2. Press and hold the "FM/AM" button on the radio for five seconds.
3. Release the "FM/AM" button.
4. Press the "1" button on the radio.
5. Release the "1" button.
6. Press the "SEEK" button on the radio until the desired radio station is reached.
The radio is now reset.
