Installing an air horn system such as the Fiamm Dixie Air Horn on a Ford F-150 involves both electrical and mechanical components. This guide provides a detailed, step-by-step breakdown of the process based on user experiences and technical details shared in various online forums and product documentation. The focus is on practical installation methods, wiring configurations, and physical mounting techniques, all of which are critical to ensuring the horn operates reliably and safely.
This guide is intended for U.S. consumers and DIY enthusiasts with a basic understanding of automotive electrical systems and mechanical installation. It does not provide marketing or promotional language, but instead offers actionable, technical insights derived from verified sources.
Overview of the Fiamm Dixie Air Horn System
The Fiamm Dixie Air Horn is a 12V-powered horn system designed to produce a loud, musical horn sound commonly known as the "Dixie tune." The system includes five trumpet horns, a compressor, a relay, and mounting hardware. The horns operate at frequencies ranging from 466 Hz to 698 Hz, with a sound pressure level of 116 dB. The compressor is typically a 3-liter unit, though slightly larger units may be used depending on available space.
The horn system is designed to be mounted in locations that are both effective and convenient for air flow. Common installation spots include behind the radiator or near the rear seat area, with wiring and tubing routed through existing channels to avoid drilling into the vehicle's body.
Electrical Configuration and Wiring
Correct electrical wiring is essential to ensure the compressor and horns receive sufficient power and are triggered reliably by the horn switch. The relay, which is a critical component of the system, must be properly connected to a high-current source and ground to avoid damage or poor performance.
Relay Terminal Connections
The relay is a four-terminal device used to control the high-current circuit to the compressor. According to user reports and technical descriptions, the following connections are typically used:
- Terminal 30 connects to a high-current source, such as a 20 or 30 amp fuse or directly to the battery.
- Terminal 87 connects to the high-current side of the compressor, ensuring it receives power when the relay is activated.
- Terminal 85 is kept hot at all times, usually connected to the same source as Terminal 30.
- Terminal 86 connects to the horn switch, which, when grounded, completes the circuit and activates the relay.
In one user's setup, the relay was configured such that the horn switch grounded Terminal 86, which triggered the relay and connected Terminal 30 to Terminal 87. This setup ensured the compressor received full power when the horn was activated.
Power and Grounding Considerations
To ensure reliable operation, the compressor should be connected using no smaller than 12-gauge wire. The ground connection should be as direct as possible, ideally running back to the battery or a solid frame ground. A poor ground connection can lead to weak horn performance or even damage to the compressor motor.
Some users also recommend installing the relay in a location that is easily accessible and well-ventilated. This helps prevent heat buildup and ensures the relay can be checked or replaced if needed.
Mounting the Compressor and Horns
Physical mounting of the compressor and horns requires careful planning to ensure the system is secure, protected from the elements, and does not interfere with other components.
Compressor Placement
The 3-liter compressor is often mounted in the space behind the rear seat. This area is typically unused and provides enough room for the compressor, wiring, and a solid ground connection. If a larger compressor is used, it is important to measure the space to ensure a proper fit.
Some users have reported success using a slightly larger compressor, provided it fits within the space and does not block access to other components. The wiring should be routed along existing channels under the floorboard panels, which allows for a clean and organized installation without the need to drill into the vehicle's body.
Horn Mounting
The horns are typically mounted behind the radiator, which provides good airflow and protects them from direct contact with road debris. An existing aluminum panel at the bottom of the radiator is often used for mounting, as it already has pre-drilled holes.
An aluminum L-bracket is commonly used to secure the horns in place. After drilling holes and bending the bracket slightly to achieve the correct angle, the mount is considered rock-solid. The horns are mounted to face forward or upward to prevent damage from carwash jets or road grime.
In some installations, the horns were mounted using an aluminum panel that was already present, which simplified the process and ensured a secure fit.
Routing Wires and Air Hoses
Proper routing of wires and air hoses is essential for both safety and aesthetics. The wiring and air tubing should follow existing channels and be kept away from sharp edges or moving parts.
Passing Through the Firewall
To pass the wiring and air hose through the firewall, some users have used a gun-cleaning rod to push the components through the rubber grommet where the main harness is located. This method allows for a clean and secure installation without the need for additional drilling.
Having a second person assist with this step is often recommended, as it makes the process easier and reduces the risk of damaging the wiring or hose.
Hiding the Wiring
Wiring should be run along existing channels under the floorboard panels to keep it out of sight and prevent accidental damage. This method also allows for a cleaner appearance and ensures the wiring is not exposed to the elements.
Some users have reported that the wiring was kept under the floorboard panels and connected to the relay in a location that was easily accessible for future maintenance.
Final Assembly and Testing
Once all components are installed and wired, the system should be tested to ensure it operates correctly. This involves activating the horn switch and listening for the full "Dixie tune" to be played.
If the horn does not sound or operates weakly, the following checks should be made:
- Ensure the relay is properly connected and functioning.
- Check the wiring for any loose or damaged connections.
- Confirm the ground connection is secure and not corroded.
- Verify that the compressor is receiving sufficient power and is not overheating.
After the system is confirmed to be working, the installation is complete. Some users have reported that the system requires minimal maintenance and continues to operate reliably for extended periods.
Conclusion
The Fiamm Dixie Air Horn is a popular upgrade for Ford F-150 owners seeking a powerful and distinctive horn sound. The installation process involves both electrical and mechanical components, and careful planning is essential to ensure the system operates reliably and safely. By following the steps outlined in this guide, users can achieve a clean and professional installation that meets both functional and aesthetic requirements.