If your vehicle is showing steering wheel buttons and horn suddenly stopped working, here are the most likely causes and the parts you'll need to fix each one.
The clockspring is a rotating electrical ribbon cable inside the steering column that connects the steering wheel electronics to the vehicle. When it snaps from age and wear, the horn, buttons, and usually the driver's airbag lose connection simultaneously.
If the steering rack or column was recently disconnected and the steering wheel was allowed to spin freely, the internal clockspring ribbon gets stretched and snaps as soon as the wheel is turned lock-to-lock.
A blown fuse can cut power to the steering wheel control module and horn circuit. This is often a secondary symptom of a short circuit somewhere in the steering column wiring or a failing horn.
If an aftermarket steering wheel was recently installed or the airbag was removed for service, the main electrical connector behind the airbag may not have been fully seated until it clicked.
The BCM processes the signals from the steering wheel buttons and triggers the horn. A software glitch or hardware failure in this module can cause these inputs to be ignored, usually accompanied by other interior electrical issues.