2. Buy a potentiometer with the same size and volume and similar resistance. A potentiometer is only a few cents.
3. If it is not the same, weld the potentiometer, open the inside, and reshape the rotating elastic sheet to make it reliably contact with the carbon film of the resistor. Originally, car stereos should use electronic potentiometers and be controlled by software. The CPU hardware and software circuit of the whole audio control chip should be completely changed, so only the volume switch or components imported from Japan are used less.
4. Just change the switch, or buy a switch on Taobao, go back and remove the panel, and just change the button yourself.