Led light

How to Wire Led Light Bar Without Relay- Your Next to Know Guide!

Nighttime driving is already pretty tricky, especially now when over 75% of the population needs specs for corrected eyesight. On top of that, if the roads are dark and unlit, the driving becomes rather a burden.

 A better solution for dark roads is that you install an LED light bar on your vehicle so you have a better vision of the road while driving.

  • Having an LED light bar on your car is one of the major necessities if you’re driving at night frequently.
  • Low lighting driving in late hours of the night is pretty dangerous.

In this article, we’ll show you how you can wire an LED light bar without a relay. Follow our guide to the point and you’ll succeed in no time!

Table of Contents


Picking out power supply:

The power supply that you choose must have suitable voltage and wattage for LED that you select. Therefore, carefully check for those when picking your power supply.

Selecting LED:

Two important features that should be the fundamental reasons for selecting the LED are its operating life and color temperature. Choose the one with a higher color temperature as you need brighter light on the road. Choose the one that has the highest lifespan as well.
Also, check compatibility with the power supply. The wattage and voltage of the power supply and LED should match.

Choosing the resistor:

Pick a resistor with low current values as the opposite will cause the light to burst. Compute the amperage and voltage when you select any resistor.


  • Make sure the switch is off before you begin the work to avoid and accidents.


  • An electric soldier
  • Electrical safety gloves
  • Copper wire (one or more depending upon the number of lights and switches you choose to use)


Select an appropriate open space to complete your task. Make sure there are no energy sources too close around that may unattended get connected to your equipment. Work in a safe and easy environment.

Lay your equipment on the ground to begin your work.


Connect the terminal of the switch with one side of the resistor with the help of a copper wire.


Use the electrical solder and solder on both ends; one on the resistor and the other on the switch terminal. Make sure you solder the ends carefully. If you’re using an electrical solder for the first time, please do not forget to read the instruction manual given along with the solder gun.


Connect another end of the terminal of the switch to the power supply. Make sure you connect it to the positive end of supply.


Again, solder both ends, carefully.


Mark this as “+’ve”. Do this to stay safe and for knowing which end is positive for any future needs.


Connect the Led’s cathode with the power supply. Solder the ends with electrical solder.


Turn on the switch of the LED light bar to see if it does light up or not. If it does, amazing job! But if somehow it doesn’t work, revise all the steps and see what you missed. Follow carefully to execute the perfect lightened up LED bar without a relay.

The wiring of the LED light bar is done here, here’s how you can successfully mount it on your vehicle.


Choose where you want the light bar to be mounted. Keep in mind; it must be somewhere that is easy to shed light on the road without distracting the driver. Check with your local authorities about regulations of the light bar being mounted on specific places to avoid any future conflicts or fines.


Mount the light bar onto the vehicle. Install the provided brackets onto the vehicle using screws and nuts. Mount the light bar onto the bracket firmly. Try to move it a bit to make sure it’s firmly mounted and not loose.


Before you begin mounting the switch, remember to disconnect the battery terminal wires so you may avoid unwanted accidents. Pick a place most convenient to you for placing the switch. It must be someplace that is easy to access while you’re driving. You must not get in the hustle of finding the switch while you’re steering the vehicle.


As your switch is already connected to your light bar, all you’ve to do now is to mount it on a specified space.


Connect the switch to the engine. Remember we’re making direct connections here, without using a relay.


Complete the circuits, both of the LED light bar and the one you disconnected in the beginning from the battery of your car. Re-test the light bar to check if you’ve done okay.


Tape all the ends, if needed use a heat shrinking tube to avoid those electric shocks. It must be safe for everyone sitting in the vehicle. No open wires shall be dangling down from anywhere.

Frequently Asked Questions

Q. Do I need a relay for LED strip lights?

When figuring LED lights, like off-road light bars, driving/work lights, or other spare lights to a vehicle, you want to add a circuit to power the light sufficiently. Relays are a value-effective, flexible way of doing this.

Q. What type of wire is used for LED light bars?

For your light bar drawing 300 watts (25A@12V), 14 gauges will cover you. Remember though that you simply don’t have to wire everything in 14 gauges. The switch and relay coil will be the smaller gauge.

Q. Can you use speaker wire for LED lights?

A lamp draws little current, mainly with advanced LED bulbs, so a decent speaker wire of even 18 or 20 gauge is ok. For higher-drawing devices, sort of a household appliance, you would be happier using heavier 16-, 14- or 12-gauge wire. The heavier wire has less resistance, so it’s less likely to blister in daily use.

Q. What size fuse do I would like for LED light bar?

 A 10 amp fuse will protect the circuit. The 16 gauge wire will handle 10 amps within the length of wire that you just are applying. The switch is rated for 20 amps. So, the ten amp fuse will protect the circuit from overload.

Q. What size fuse should I exploit for LED lights?

75mm is sweet for about 7.5 amps max. I generally favor having a minimum of 100% extra rating so; a 3 amp fuse max is what I had used. That could be plenty for 4 LEDs. If you have got working LEDs but blow a 10A fuse I believe your wiring needs checking and you’ll probably find your fuse is direct across the battery.

Q. Do LED light bars to draw lots of power?

 A genuine 120W LED bar would be brighter than the most glorious set of car high beams. LEDs use about one-fifth the ability for the identical amount of light output. So for your light bar, it might consume one-fifth of the present, i.e. 0.2 amps from a 120 VAC source, or 2 amps from the lead-acid accumulator.

Q. What are the three wires on LED lights?

LED Lights with 3 wires are a multi-function light. They will (most times) be utilized in whatever configuration is correct for your application. For example running and brake, running, and blinker, or brake and blinker. These LED’s will normally have a black, red, and white wire.

Bottom Line

Wiring an LED light bar without relay isn’t truly encouraged, but if you’re sure about wattages and amperage then go ahead and do this. We’ve told you the easiest way to light up your LED light bar and we’ve also included a guide about mounting the light bar onto your vehicle. It sure isn’t as tough a job. Just keep safety and precautions in practice and you can accomplish this in no time.

Good luck with mounting your LED light bar on your vehicle and hitting the road with some lights!

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