How To Install A Light Bar

The following steps detail installing a light bar on a 2013 Ford F150. The light bar we’ve chosen for this demonstration is an NVision 20” triple row combo light bar. One important choice you’ll have to make is where to mount the light bar on your vehicle. In this case, we’ll be bolting it to the frame under the grille. You may choose to mount it on the bumper, roof, cowl, or other location. Just keep in mind, moving the light too far away from the battery may require modifications to your wiring harness.

To simplify the installation, we’ll be using a 2-Light Quick-Connect Wiring Harness, also from NVision. If you purchase a pre-made wiring harness, it will already include the toggle switch, fuse and fuse holder, and a relay, all with quick connectors to simplify the installation.

However, it is possible to build your own wiring harness. To do this, you will need 16 gauge wire in two different colors, an in-line fuse holder and fuse mounted no more than 12 inches from the battery, and a toggle switch to turn the light on and off. Make sure the fuse and toggle switch are rated for the current draw of the light, otherwise they may fail frequently. We won’t be showing you how to build the wiring harness today; these instructions will pertain to the installation of a wiring harness.

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Step 1: Measure for light bar placement

Begin by measuring for your light bar mounts. Size and mounting point information or a mounting template is usually printed on the box or in the supplied instructions.

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marking drill holes for light bar installation

Once you’ve got your measurements, use a chalk marker or something similar to mark where you’ll drill your holes.

Do It Right: In the case of a plastic bumper, you may have to find part of the frame underneath the bumper to securely mount the light bar. Metal bumpers are easier, and keep the light bar secure in any position, but the bolts may pull through plastic.

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Checking for airbag sensors before drilling

Step 2: Drill holes and place the light bar

Before drilling, you’ll need to make absolutely sure there aren’t any airbag sensors or other parts that could be damaged by drilling in the specific area you’ve chosen to mount the light.

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Drilling Holes to mount light bar on truck

Once you’ve made the marks for your light bar brackets, carefully drill the holes.

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test fitting light bar on truck before installing light bar

After the holes are drilled, test fit your light bar and mounts. If you’re satisfied with your placement, bolt the light bar mounts in place using the supplied bolts, which are tamper-proof. For that reason, we also have a special bit to install them.

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Now that the light bar is mounted, we can run the wiring harness. The wiring harness that we’re using includes the toggle switch, relay, and fuse holder needed for installation, as well as the ring terminals to connect to the battery terminals.

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disconnecting negative truck battery terminal

Step 3: Mount the toggle switch

Begin by disconnecting the negative terminal of the battery, to prevent a short circuit.

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passing connector wires through rubber grommet in vehicle firewall

Then, disconnect the toggle switch quick connector, and pass the connector and wires through the rubber grommet in the firewall. On most vehicles, there will be a bundle of wires passing through a rubber grommet near the base of the steering column in the engine compartment. Once the quick connector is through the firewall, find the end inside the vehicle’s cabin.

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drilling hole in dashboard for light bar toggle switch

At this point, you should mount the toggle switch. This can be done by drilling a hole slightly smaller than the diameter of the switch in the area on the lower dashboard, or wherever you intend to mount the switch.

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pressing light bar toggle switch into place on truck dashboard

Once you’ve drilled your hole, press your toggle switch into place. The toggle switch has ears that won’t allow it to slip back through once it is installed.

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Connecting plug from toggle switch to quick connector

Connect the plug from the toggle switch to the quick connector that you passed through the firewall.

Do It Right: You may need to tuck the extra wire or use wire ties to secure it out of the way of your brake or clutch pedals.

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routing wires through engine compartment

Step 4: Route the wire through the engine compartment

Now you can move back to the engine compartment. Route your wires where you can ensure they won’t touch anything that could melt or puncture the insulation. Wire ties may also be necessary during this step to secure the wiring. Mount your relay to a metal surface under the hood using a self-tapping screw. You can also wire your ground cable to a metal surface or directly to the battery using the ring terminal.

Do It Right: Don’t forget to ensure that the positive ring terminal of the wiring harness can reach the battery. If not, you may need to splice an extension wire and new ring clip in place.

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Step 5: Connect wiring harness to light bar

Now, you can pass the lighting wires through to the front of the vehicle. Our wiring harness includes wiring for two lights, but since we’re only wiring one, we’ll want to cap or tape the ends of the extra connection to ensure it does not ground out.

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routing wire for light bar through grill of truck

Route the wire you’re using through the grille of the vehicle near the light bar, ensuring you’re not touching the radiator or any other potentially hot parts.

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crimping wire to attach wiring pigtail to light bar

At this point, use a butt connector and crimping tool to attach the supplied wiring pigtail to the light bar.

Do It Right: The butt connectors we’re using have built in heat-shrink, but if you’re going to use separate cut-to-size heat-shrink, you’ll need to place it over the wiring before you attach the butt connector.

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heat shrink the butt connector attachment

You can now heat-shrink the attachment. You can also use electrical tape to secure the attachment.

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plugging in the wire harness to quick connector

Now, plug in the harness quick-connector. Check to make sure all of your wires are secured away from other parts before moving to the next step.

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Step 6: Reconnect battery and test light bar

Connect the positive wire ring terminal from the wiring harness to a power source or the battery, and then reconnect your battery.

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Time to test the light bar. Flip the switch and make sure it lights up!

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The automotive repair work depicted in this series is performed under the direction of the manufacturer of the product featured. Prior to undertaking any of the demonstrated repairs on your vehicle, we suggest you consult with a certified mechanic or another professional who can adequately advise you of the proper repair or remedy required. O’Reilly Automotive Stores, Inc. and its affiliates (“O’Reilly”) disclaims any responsibility for injury or damage resulting from a viewer’s attempt to recreate the repairs shown in this series.

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