Full disclosure: I'm a complete novice with electrical engineering.

I'm trying to wire a lightbar to my 2015 Jeep Wrangler Unlimited Sport.

Lightbar: https://www.amazon.com/dp/B012CGFOOQ/ref=cm_sw_r_cp_apa_tTevAbN7W80PD

Wiring: https://www.amazon.com/dp/B00O72R7Z8/ref=cm_sw_r_cp_apa_ZTevAbWJRGZJ9

I wired red to red and black to black between the lightbar and the wiring. I bolted the round connectors to the car battery (black to negative terminal, red to positive terminal). I zip-tied the relay to the body of the Jeep.

I tried the toggle switch with each fuse. Only the purple fuse (labeled "3") turned the light on, which was only for a quarter second. The other fuses were labeled 5, 5, and 7.5.

I'm not sure why all fuses burned out. Did I wire something incorrectly? Are the wires not compatible? Do I need a larger fuse?

  • 1
    Welcome to Motor Vehicle Maintenance & Repair! Commented Jan 9, 2018 at 5:24

4 Answers 4


If you wired it as you say, as the wiring diagram on the Amazon page shows, it should work. That's the correct wiring for that setup.

The issue is that you got a wiring kit that says it handles 180W max, yet came with a 7.5A fuse. That's suspicious. What does the relay say, is it really 40 Amps? You could stick a larger fuse, but it may still not work, if the wires are too thin for your load.

Your load being a 120W or 10 amp light. You need a 10 amp or larger fuse. Next normal sizes up are 12.5 or 15 amps.

You can test the wiring, and relay and button by using a small fuse and a small load. Replace the light bar with a small light, or remove it completely. Press the button. The button should light up and the relay should click without issue.


The 120 Watt light bar will draw about 10 Amps at 12 volts. You will need a 15 or 20 Amp fuse for it.

  • Good call! And if you are running two of these light bars, you're going to need a system which can run 20A minimum, so probably ~30A worth of fuse and wiring. Commented Jan 9, 2018 at 15:11

There should be two fuses in this system. One big one ( 20-30 Amp ) feeding the relay, and a second smaller one in the lead to the switch.

The switch (if connected properly) only powers the relay coil so that fuse will be pretty small. You could possible run that line off your accessory circuit (thus using a vehicle fuse).

Hopefully the instructions that came with the thing are better than whats on the amazon page. I'm concerned by "quick install" #3 which appears to tell you to run it to the battery un-fused. Very dangerous especially considering you've likely run that line through the firewall into the cab somewhere.

  • would not wire it directly to the battery, I would at the fuse box. In your owners manual look for a compatible fuse that will be for accessories. Double check that ,Assuming *digital lights are all plugged in appropriate to is lamp connector as it will not work proper if even one light is plugged in backwards. Many a time some one will take out a light just to examine it. You could take each bulb and test individually by making a makeshift connector for testing (other lighting connector/ clipping a positive and negative wire and test from the battery.
  • Bad idea. The fuses in the fuse box are there to support their function. They wouldn't be able to handle an additional 20A load. This is what the inline fuse in the wiring is for, to protect the system. Commented Jan 9, 2018 at 15:14

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