From VIN S5220000

Battery voltage is supplied at all times to both the coil and the contacts of the horn relay from the STOP fuse. When horn switch is pressed, the coil of the horn relay is grounded through either a horn ring or clock spring. The horn relay then energizes and applies battery voltage to the horn, causing it to sound. The horn can also be grounded by the electronic time and alarm control module. See the Theft Deterrent system, for details.