How do you enter the code on a radio of 1982 Mercedes 300 SD turbo desil?

To enter the code on a radio of a 1982 Mercedes 300 SD turbo diesel, follow these steps:

1. Turn on the radio.

2. Press the "code" button. The display will show "code?".

3. Enter the four digit code using the preset buttons 1-6.

4. Press the "enter" button. The display will show "code accepted" and the radio will turn on.

If you do not know the code, you can contact a Mercedes-Benz dealer or an automotive locksmith to retrieve it.