How to Install Accessory Wiring on a Motorcycle｜BLIAUTO Practical Guide for Motorcycle Lighting & Accessories

As motorcycle modification culture continues to grow, more and more riders are choosing to add LED strips, USB chargers, dash cams, warning lights, or additional headlights to their bikes—whether for practicality or style. However, no matter which electrical accessory you're installing, correct wiring is always the most crucial part of the process. Improper wiring can lead to short circuits, blown fuses, battery drain, or even safety hazards on the road.

BLIAUTO is here to walk you through the essential steps for installing motorcycle accessory wiring, including common wiring techniques, safety precautions, and typical circuit examples—making your motorcycle electrical upgrades safe and simple.

I. Preparation Before Wiring Installation

Proper preparation before getting hands-on can greatly reduce errors:

1. Confirm Voltage and Power Requirements of the Accessory

Most motorcycles use a 12V DC electrical system. Before wiring, confirm the accessory's rated voltage (typically 12V) and its power consumption to determine whether you need a relay, fuse, or a separate power control module.

2. Gather Essential Tools and Materials

Wire stripper / crimping tool

Multimeter (to measure voltage and locate power lines)

Electrical tape / heat shrink tubing (for insulation)

Power cable (preferably dual-core copper wire, ≥0.75mm² cross-section)

Terminal connectors, fuse holders, relays, etc.

3. Refer to the Wiring Diagram or Vehicle Manual

It’s recommended to check your motorcycle’s user or service manual to locate the battery, ignition switch, fuse box, and accessory lines to avoid miswiring.

II. Where to Source Power: Choosing the Right Power Tap

1. Direct Battery Power (Recommended for High-Power Accessories)

Run a main power line from the battery's positive terminal (through a relay and fuse) to power high-wattage accessories like spotlights or speakers. Always install a fuse (5–15A depending on load) close to the battery.

Pros: Stable power supply, doesn't affect OEM wiring

Cons: Requires relay setup, slightly more complex

2. Ignition-Controlled Power (For Low-Power Devices)

You can tap power from an ignition-switched source (commonly the ACC line). This way, accessories like USB chargers or LED DRLs only receive power when the ignition is on, preventing battery drain.

Pros: Power cuts off with ignition, easier to manage

Cons: Finding the ACC line requires a multimeter

3. Fuse Box Tap (Beginner-Friendly Option)

Some bikes have spare or empty fuse slots in the fuse box. You can use a "fuse tap" to connect accessories like dash cams or GPS units.

III. Wiring Techniques and Important Considerations

1. Choose a Logical Routing Path

Avoid areas near the engine, hot exhaust pipes, or moving parts

Route wires along the factory wiring harness and secure with zip ties

Use a wire puller or guide wire to avoid forcing wires through tight spaces

2. Protect Wires from Damage

Use heat shrink or corrugated tubing to cover exposed wires

Where wires pass through sharp edges, use rubber grommets for protection

Leave slack near the battery and under the handlebar to prevent tension during steering

3. Ensure Secure, Waterproof Connections

Use crimp tools for terminals and cover with heat shrink

Avoid twist-on connections—solder or terminals are more secure

For exposed outdoor connections, seal with silicone or heat-shrink waterproof sleeves

IV. Recommended Wiring Examples

Example 1: Installing LED Daytime Running Lights

Tap power from the ACC line or an ignition-switched fuse

Control method: individual switch or parallel to headlight circuit

Add a 1A fuse for protection

Example 2: Adding a USB Charger

Tap power from the post-ignition line (usually red wire)

Use a waterproof USB head with built-in voltage regulation (12V to 5V)

Add a 1–2A fuse

Example 3: Installing External LED Spotlights (Auxiliary High Beam)

Battery positive → Fuse holder → Relay → Switch → LED Spotlight

Ground the light to the chassis

Use a 10–15A fuse; remote switches are a plus

V. Final Inspection and Testing

Use a multimeter to verify voltage and ensure no shorts

Start the engine and test accessories to confirm normal operation

Check OEM functions like lights, gauges, and ignition

Look for signs of blown fuses, burning smell, or overheating

VI. Safety Tips & Common Mistakes to Avoid

Don’t run multiple high-power devices from one thin wire—it may overheat and catch fire

Don’t route power wires under the gas tank unprotected—this risks damage or short circuits

After installation, regularly check for wire wear and loose terminals

Avoid overloading the bike’s electrical system (typically 180–350W max output)

Conclusion

While installing accessory wiring on a motorcycle might seem straightforward, achieving a safe, stable, and durable system requires attention to detail and correct wiring practices. Whether you’re adding stylish lights or functional upgrades, following proper electrical design and routing will ensure your motorcycle performs reliably and looks great.

If you have any questions about motorcycle electrical upgrades, feel free to contact BLIAUTO's professional lighting team. We offer one-stop support for accessory selection, circuit planning, and installation guidance!