There are several reasons why your BMW horn may not be working. Here are a few common causes:
Fuse: The horn is usually connected to a fuse that can blow out, causing the horn to stop working. Check your owner’s manual to find the location of the fuse box and see if the horn fuse has blown.
Wiring: The wiring that connects the horn to the rest of the car may have become loose, corroded, or damaged, causing a break in the circuit. This can prevent the horn from working properly.
The horn itself: It’s also possible that the horn itself is faulty or damaged. If the horn has been exposed to water or moisture, it may have rusted or corroded, preventing it from working.
Steering wheel: If the horn button on your steering wheel is not functioning properly, it may prevent the horn from working. Check to see if the airbag module is stuck or if there is any damage to the steering wheel.
Broken coil spring: The horn’s steering wheel wiring is connected to the car via a coil spring integrated into the steering column switch cluster. The usual telltale sign of a broken coil spring is the Airbag light and/or non-working steering wheel buttons.
If you are unable to diagnose and fix the issue yourself, it may be best to take your BMW to a professional mechanic or BMW dealership to have it properly diagnosed and repaired.