DIY Horn Upgrade: A Diagrammed Installation Guide

Upgrading your car's horn isn't just about making a louder noise; it's about enhancing safety and potentially saving lives. A weak, pathetic peep is far less likely to alert other drivers to your presence than a strong, clear blast. This comprehensive guide will walk you through a DIY horn upgrade, providing clear instructions and diagrams to help you achieve a more assertive horn sound. We'll cover everything from selecting the right horns to safely installing them.

Choosing the Right Horns

Before you even think about tools, you need to select the right horns for your vehicle. Several factors influence your choice:

• Sound: Do you want a deep, resonant tone, a high-pitched shriek, or a combination? Many aftermarket horns offer dual-tone options for maximum impact.
• Loudness: Measured in decibels (dB), louder horns are more effective but may be subject to local noise ordinances. Check your local regulations before choosing excessively loud horns.
• Size and Fit: Ensure the horns you choose will physically fit in the space allocated under your hood. Measure the available space carefully before purchasing.
• Voltage: Make sure the horns are compatible with your car's electrical system (typically 12V).

Popular Horn Types:

• Air Horns: These produce a powerful, compressed air sound, often favored for trucks and larger vehicles. They require an air compressor, making them more complex to install.
• Electric Horns: The most common type for DIY upgrades, these are relatively simple to install and require only a 12V power source. They offer a wide range of tones and loudness levels.

Tools and Materials You'll Need

Before you begin, gather the necessary tools and materials:

• New Horns: Choose your horns based on the criteria above.
• Relay: A relay is crucial for high-amperage horns. It protects your vehicle's wiring.
• Wiring Harness (Optional): Pre-made harnesses simplify wiring, especially for dual-tone horns.
• Wire Strippers/Crimpers: For connecting wires securely.
• Soldering Iron and Solder (Optional): For a more robust and professional connection.
• Electrical Tape: To insulate connections.
• Socket Wrench Set: For removing the existing horn.
• Screwdrivers (Phillips and Flathead): For various fastening tasks.
• Zip Ties: For securing wiring.
• Multimeter (Optional): To test wiring and voltage.

Step-by-Step Installation with Diagrams

(Diagram 1: Existing Horn Wiring – A simple diagram showing the existing horn's wiring connected to the steering wheel horn button. This should show positive (+) and negative (-) wires.)

(Diagram 2: New Horn Wiring with Relay – A detailed diagram showing the new horns wired to a relay, with the relay controlled by the steering wheel horn button. This should clearly show the power source (+), ground (-), horn trigger wire, and connections to the horns.)

Step 1: Disconnect the Battery Negative Terminal

This is crucial for safety. Disconnect the negative (-) terminal of your car battery before starting any electrical work.

Step 2: Remove the Old Horn(s)

Locate your existing horn(s), usually mounted under the hood. Use the appropriate socket wrench to remove the mounting bolts and detach the wiring harness.

Step 3: Install the Relay (if using)

Mount the relay securely in a suitable location under the hood. Refer to the relay's instructions for wiring details. The relay will act as a switch, handling the high amperage of the new horns without overloading your vehicle's wiring.

Step 4: Wire the New Horns

Connect the positive (+) wire from the battery to the relay's power input terminal. Connect the negative (-) wire from the relay to the ground. Connect the positive wires of your new horns to the output terminal of the relay. Connect the negative wires of your new horns to the ground.

Step 5: Connect the Horn Trigger Wire

Connect the horn trigger wire from the steering wheel horn button to the relay's trigger wire. This completes the electrical circuit.

Step 6: Secure the New Horns

Mount the new horns securely in the designated area. Use the provided mounting hardware or appropriate bolts.

Step 7: Connect the Battery Negative Terminal

Reconnect the negative (-) terminal of your car battery.

Step 8: Test the New Horn

Press the steering wheel horn button to test your new horn. If it doesn't work, double-check all your connections.

Troubleshooting

• Horn doesn't work: Check all connections, fuses, and the relay. Use a multimeter to verify voltage and continuity.
• Horn is too loud: Consider installing a smaller or lower-decibel horn, or using a horn relay to help control the sound.
• Wiring issues: Incorrect wiring can lead to malfunctions. Always double-check connections and refer to the diagrams.

What if my car has an integrated horn system?

Some vehicles use integrated horn systems that aren't easily replaceable with aftermarket parts. For these scenarios, consulting a professional mechanic is advised.

How do I find the right relay for my horn upgrade?

The ideal relay for your horn upgrade depends on the amperage draw of your new horns. Consult the specifications of your chosen horns to determine the appropriate relay rating. Ensure the relay is appropriately rated to handle the current draw of your new horns without overheating or failure.

Are there any legal restrictions on horn loudness?

Yes, many jurisdictions have noise ordinances that restrict the loudness of vehicle horns. Before purchasing and installing new horns, research your local regulations to ensure compliance.

This detailed guide, along with the accompanying diagrams, should help you successfully upgrade your car's horn. Remember safety first! If you are not comfortable working with car electrical systems, consult a qualified mechanic.