How to Troubleshoot a BMW Sound System

1. Check the fuses in your BMW in case one of the stereo components stopped working due to a blown out use. Your fuse box, depending on your BMW model, can be found in the trunk, glove compartment or the hood. Use the diagram in the manual and also under the case of the fuse box which tells you which fuse and number is associated with the stereo system components.
2. Check your speakers to determine if there is loose wiring that can cause a cracking, popping or lack of sound. BMWs have speakers located on the doors, back seats, back windshield and dash. You may need to unscrew certain components like the door enclosure in order to access the speakers. Look for loose wires or faulty wires. You may need to replace the speaker or solder the loose wire back onto the speaker.
3. Clean CD changers or stereo components using electronic cleaners, like compressed air. Spray the compressed air between the shift knobs and in between the slots of your CD changer. Older BMWs have knobs that can become loose and can cause erratic volume issues. Cleaning the stereo components can fix this.
4. Check for error codes that may be displayed on the BMW stereo system. Also, if you're required to input a security code, the battery could have died or was removed temporarily, as well as other electronic components affecting the stereo system. Check with your BMW dealer to obtain the security code, which may allow the stereo to start functioning again.
5. Check any previous work that was done to the stereo system. Some BMW models may experience issues after installing auxiliary or iPod connectors, which may cause issues with the stereo system.