horn doesn't blow when pressed, but alarm horn works

The alarm horn is inside the engine compartment the horn you press from the steering wheel is located behind the driver's front bumper cover, they are seperate circuits. The horn behind the bumper has a black/yellow wire attached to it, supply power to that wire and see if the horn works. The horn has a relay in the circuit and a spiral cable (part of air bag system) to allow the horn to work as you turn the steering wheel.