Principles of Operation
WARNING: This page is about a different car, the 2007 Ford Pickup, 2007 Ford F550 Super Duty, 2007 Ford F450 Super Duty, and 2007 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
The horn switch is incorporated within the driver air bag module. The horn switch is serviced separately from the driver air bag module. When the switch is closed, ground is supplied through the clockspring from the vehicle harness. The horn relay is then energized, supplying voltage to the horns and enabling the horns to sound. The horn relay is integral to the central junction box (CJB).