Dual Horn Wiring Diagram - Air Horns & Stock Horns with Relays & SPDT Switch

This is a hand-drawn wiring diagram (created in a basic drawing program) showing how to wire dual horn systems — aftermarket air horns and factory stock horns — on one vehicle using two relays and a selector switch. A constant 12V feed (drawn in red) supplies both relay triggers, each labeled 'Trigger for relay always hot,' as well as the load circuits. The factory horn switch provides a ground path, and a single pole double throw (SPDT) switch placed between the horn switch and the two relays determines which relay coil is grounded when the horn button is pressed. Depending on the SPDT switch position, either the relay feeding 'my air horns' (left side) or the relay feeding 'the stock horns' (right side) is energized. The diagram uses red lines for constant 12V power and dark blue lines for the switched ground/trigger circuit. No fuse ratings, wire gauges, wire colors codes, part numbers, or relay pin numbers are given; it is a conceptual schematic rather than a factory diagram. It was uploaded to a 1986 Ford Bronco gallery alongside related horn, hub, and steering column documents, and is useful for anyone wanting to toggle between air horns and stock horns using the original horn button.