Wiring an LED light bar or a set of driving lights is easier than it looks once you know what each part does. Most off-road lights need four things: the light, a wiring harness with a relay and fuse, a switch, and the right connectors or extension cables. This guide explains each part in plain language, shows which harness and switch fit which setup, and answers the questions we hear most from Canadian overlanders. Prices are in CAD as listed at Union Overland in October 2026.
Safety first: disconnect the battery before you start, follow the manual that comes with your light, and if you're not comfortable working on vehicle wiring, have a qualified installer do it.
A wiring harness kit includes the wiring, relay and fuse in one package.
What Do You Need to Wire an LED Light Bar?
- The light itself. Many Siberia lights are sold individually and don't include a harness. Check your product page for what's included. For example, the 22" Siberia XP Single Row has an integrated relay and a 2,500 mm cable, so it doesn't need a relay harness.
- A wiring harness. It carries power from the battery to the light through a relay, protected by a fuse.
- A switch. It turns the light on and off from inside the vehicle.
- Connectors and extension cables. These let you reach from the light to the harness.
- Brackets. See mounting brackets for options.
Why Do I Need a Relay and a Fuse?
A light bar can draw a lot of current, and a small dash switch shouldn't carry that load. A relay lets the switch send a small signal that turns the high-current power on and off. A fuse protects the wiring and the vehicle if something goes wrong. Plug-and-play harnesses include both, so you don't have to buy and assemble them separately.
Which Wiring Harness Do I Need?
Pick the harness that matches how many lights you're connecting and how much power they draw. Add up the wattage of your lights and compare it with the harness's listed limit.
| Harness | Price (CAD) | Listed details |
|---|---|---|
| Wiring Harness – Single Lamp | $60 | 30A harness with switch, in-line relay and DT connector; up to 156 W |
| Wiring Harness – Two Lamps | $78 | 30A harness with one switch and two DT ends; up to 120 W per lamp; 9' from the DT connector to the relay |
| Single Lamp w/ Dual Position Lights | $95 | 40A relay, 30A in-line fuse, main power switch and dual-colour position light switch; 3 m from the DT connector to the relay; DT connectors rated to 156 W |
| Two Lamps w/ Dual Position Lights | $129 | For two lamps with dual position lights |
| Three Lamps w/ Dual Position Lights (Siberia Pro High Power Harness Kit) | $189 | Up to three lights at 3 x 145 W with DT connectors; includes a 70A relay, 50A fuse and three DT-4 to DT-2 adapters; no switch included |
| Heavy Duty (DTP) – Single Lamp | $78 | Plug-and-play for a single lamp of 300 W or less with the heavy-duty DTP connector; not for lamps with standard DT2 connectors |
If your light has no connector, or you need more power than the DT connectors are rated for, some harnesses can be cut at the connector and hardwired. The three-lamp kit, for example, is listed at 550 W if the DT connectors are cut off. Follow the instructions for your harness, and note that the three-lamp kit says to cut at least 50 cm from the relay.
How Much Power Does My Light Bar Draw?
Check the wattage on your light's product page, then divide by 12 to estimate the amps at 12 V. For example, the 22" Siberia XP Single Row is listed at 102 W in Xperience mode, roughly 8.5 amps. The 32" Siberia XPA Single Row is listed at 166 W, roughly 13.8 amps. That 166 W is higher than the 156 W limit listed for the DT connectors on the single-lamp harnesses above, so if you're wiring a larger bar, contact us and we'll help you choose the right harness.
Do Siberia Lights Need an Adapter?
Possibly. Siberia lights have a DT-4 connector, while our BrightSource relay harnesses use a DT-2 connector. The Adapter for Dual Position Lights ($20) goes between a Siberia light and a BrightSource relay harness, and one is needed for each light. The harness runs the main beam only. The yellow and white wires on the adapter operate the dual white/amber position light, and you connect them to a power source such as the parking lights, or to a separate switch. Check your light's product page for the harness it recommends.
What Extension Cables and Splitters Are Available?
- DT4 Extension Cable in 3 m ($49) and 5 m ($87).
- DT2 Extension Cable in 0.5 m ($19), 3 m ($43), 5 m ($69) and 10 m ($129).
- DT4 Splitters for 2 lights ($26), 3 lights ($32), 4 lights ($40) and 5 lights ($48). The 2-light splitter lists a maximum input of 150 W, and 75 W per plug.
- Wiring Concealer (1200 mm, $34) for a tidy install.
Browse everything in switches, wiring and lens covers.
What Switch Should I Use?
- Lighted Rocker Switch ($14): a simple illuminated on/off (SPST) switch that fits a 3/4" (20 mm) hole. It's the same switch that comes with the single and two-lamp harnesses.
- Dual-Colour Position Light Switch ($27): changes the position light between white and amber.
- 4 Position Multi Switch Kit ($178): an all-in-one controller with integrated relays and four buttons, each programmable for on/off or momentary use, with a 20A combined output and dash mounting.
- Multifunctional Switch Kit (6 gang $249, 8 gang $279, 12 gang $299): a switch panel with constant, momentary, flash and strobe modes, five brightness levels and a choice of ACC or direct-battery power. It's rated for 12V and 24V and IP65.
How Do You Wire an LED Light Bar? The Basic Steps
The exact steps depend on your harness and vehicle, so always follow the instructions that come with your parts. In general:
- Disconnect the battery.
- Mount the light with its brackets and plan where the cable will run.
- Mount the relay near the battery and route the harness, keeping the wiring away from heat and moving parts.
- Connect the harness to the light using the DT connector, or an adapter or extension cable if you need one.
- Run the switch wiring into the cabin and mount the switch where you can reach it.
- Make the power and ground connections as the harness instructions describe, then reconnect the battery.
- Test the light and secure the wiring.
The three-lamp harness has a trigger wire instead of a switch, which ideally connects to the high beam function. It also has a cover that protects the wiring from impact, dirt, ice and water.
Which Wiring Parts Go With Which Setup?
- One light with an integrated relay (like the 22" Siberia XP): no harness needed. Check the manual for the switch wiring.
- One light, plug and play: a single-lamp harness, plus the DT-4 to DT-2 adapter if your light needs one.
- Two lights from one harness: a two-lamp harness, or a single harness with a 2-light DT4 splitter within the listed power limits.
- Three lights: the three-lamp high-power harness kit.
- Several accessories (lights, air compressor, fridge and more): a multi-switch kit.
LED Light Bar Wiring FAQ
Do I need a relay to wire an LED light bar?
Yes, unless the light has one built in. A relay lets a small switch control the high-current power. Plug-and-play harnesses include one.
Does an LED light bar come with a wiring harness?
Not always. Many Siberia lights are sold individually without a harness, and some, like the 22" Siberia XP, have an integrated relay. Check the product page.
Can I wire two lights to one harness?
Yes, with a two-lamp harness or a splitter, as long as you stay within the harness and splitter power limits. The 2-light DT4 splitter lists a 150 W maximum input.
How do I wire a light bar to the high beams?
Some harnesses have a trigger wire for this. The three-lamp harness, for example, has a trigger wire that ideally connects to the high beam function. Follow the harness instructions and check local rules on using auxiliary lights on the road.
Can I install an LED light bar myself?
Many people do, using a plug-and-play harness. If you're not comfortable with vehicle wiring, have a qualified installer do it.
How do I know which harness fits my light?
Check the "Wiring Harness Options" on your light's product page, then compare the light's wattage with the harness limit. Not sure? Contact us and we'll point you to the right parts.
Shop Off-Road Lights and Wiring at Union Overland
New to off-road lighting? Start with our guide to light bars vs driving lights vs pod lights. When you're ready, browse LED light bars, driving lights, switches and wiring and mounting brackets, or contact us and we'll help you put together the right setup.