how do you input radio code
If you interrupt the power source (disconnect the fuse or battery), the radio wll ask for a code when you reconnect the power. "Enter code" appears on the LED. Enter the code by pressing the numbered buttons and it should unlock. If you do not have the code, go to your BMW dealer and they might be able to obtain it by providing BMW the VIN. If you have tried to enter a code unsuccessfully more than about three times, the radio locks permanently, making it useless. It's an anti-theft feature. The only option is to replace the unit.
Take a look at this site about car radio codes (I'm not sure that your car radio model is included) http://car-radio-unlock.blogspot.com
Looking for a Used 3 Series in your area?
CarGurus has 31,416 nationwide 3 Series listings starting at $1,000.
Search BMW 3 Series Questions
BMW 3 Series Experts
Related Models For Sale
Used Cars For Sale