Wiring Harnesses

Wiring Harnesses: the plug-and-play link between your switch, your relay and your lights

A wiring harness is the pre-built loom that carries power and signal from your battery and switch to whatever you are running - auxiliary lights, a light bar, a set of back-up lamps, or a trailer connector. The right harness does the heavy lifting a bare wire run can't: it locates the relay, fuses the circuit, hands you a labeled switch, and terminates in the correct connector so a light bolts up instead of being spliced in. If you have added lighting and want it switched cleanly instead of hacked into an existing circuit, this is the part that makes the install honest and serviceable.

What ThreePiece stocks

There are 34 wiring harnesses in this category right now, spread across 10 brands. The current in-stock price range runs from $32 to $222 - that is what is on the shelf today, not a standing offer. Rigid Industries and Baja Designs lead the range with seven products each, followed by Diode Dynamics with six and Kuryakyn with five. KC HiLiTES, ORACLE Lighting, NAMZ, Hella, ARB and Westin round out the rest.

The stock splits into a few clear jobs. Light harnesses with a relay and switch are the bulk of it - the KC HiLiTES harness with 40 AMP relay and LED rocker switch is built for up to two 130w lights, and the KC HiLiTES FLEX ERA harness adds a 3-position switch and a 3-pin Deutsch connector. Rigid Industries covers back-up lighting with a 25-inch harness with 3-position switch and a simpler 360-Series 2-wire harness. On the trailer side, Kuryakyn offers a 4-wire trailer harness and a 4-wire harness for 14-up Touring models (excluding Trikes), which is the top of the price range.

How to choose

Match the harness to the load and the connector, not the price. A relay-and-switch harness rated for your light's wattage - like the KC HiLiTES units above - keeps the current off your factory switch. If you are only feeding low-draw lights, a simpler 2-wire harness costs less and does the job. Trailer wiring is its own path: the Kuryakyn 4-wire harnesses are model-specific, so read the fitment before you buy. Confirm the connector on your lights matches the harness end, because a Deutsch plug and a bare-lead harness are not interchangeable.

What else you'll need

Most harnesses here go in alongside the lights they power. Browse Lighting and LED Light Bars for the lamps, or add Headlights, Tail Lights and Turn Signals from the same Exterior section.

Fitment and ordering

Only three products list detailed vehicle fitment, sampling makes like Toyota, Harley-Davidson, Chevrolet and GMC across a 1999-2025 year range - so check the listing and, if you are unsure, get fitment help by phone at 813-535-5801 or through contact us. Every order ships free, and Affirm and Katapult financing is available at checkout.

Wiring Harnesses: the plug-and-play link between your switch, your relay and your lights

A wiring harness is the pre-built loom that carries power and signal from your battery and switch to whatever you are running - auxiliary lights, a light bar, a set of back-up lamps, or a trailer connector. The right harness does the heavy lifting a bare wire run can't: it locates the relay, fuses the circuit, hands you a labeled switch, and terminates in the correct connector so a light bolts up instead of being spliced in. If you have added lighting and want it switched cleanly instead of hacked into an existing circuit, this is the part that makes the install honest and serviceable.

What ThreePiece stocks

There are 34 wiring harnesses in this category right now, spread across 10 brands. The current in-stock price range runs from $32 to $222 - that is what is on the shelf today, not a standing offer. Rigid Industries and Baja Designs lead the range with seven products each, followed by Diode Dynamics with six and Kuryakyn with five. KC HiLiTES, ORACLE Lighting, NAMZ, Hella, ARB and Westin round out the rest.

The stock splits into a few clear jobs. Light harnesses with a relay and switch are the bulk of it - the KC HiLiTES harness with 40 AMP relay and LED rocker switch is built for up to two 130w lights, and the KC HiLiTES FLEX ERA harness adds a 3-position switch and a 3-pin Deutsch connector. Rigid Industries covers back-up lighting with a 25-inch harness with 3-position switch and a simpler 360-Series 2-wire harness. On the trailer side, Kuryakyn offers a 4-wire trailer harness and a 4-wire harness for 14-up Touring models (excluding Trikes), which is the top of the price range.

How to choose

Match the harness to the load and the connector, not the price. A relay-and-switch harness rated for your light's wattage - like the KC HiLiTES units above - keeps the current off your factory switch. If you are only feeding low-draw lights, a simpler 2-wire harness costs less and does the job. Trailer wiring is its own path: the Kuryakyn 4-wire harnesses are model-specific, so read the fitment before you buy. Confirm the connector on your lights matches the harness end, because a Deutsch plug and a bare-lead harness are not interchangeable.

What else you'll need

Most harnesses here go in alongside the lights they power. Browse Lighting and LED Light Bars for the lamps, or add Headlights, Tail Lights and Turn Signals from the same Exterior section.

Fitment and ordering

Only three products list detailed vehicle fitment, sampling makes like Toyota, Harley-Davidson, Chevrolet and GMC across a 1999-2025 year range - so check the listing and, if you are unsure, get fitment help by phone at 813-535-5801 or through contact us. Every order ships free, and Affirm and Katapult financing is available at checkout.