How to Wire Auxiliary Lights on a Truck

If you enjoy spending time outdoors, chances are you’ve gone camping or hiking at some point. Having a good set of auxiliary lights can make all the difference. Here’s a guide on how to wire additional lights on your truck.


Choosing the Location

When choosing a location for your auxiliary lights, keep in mind the following:

  • The location should be easily accessible so that you can reach it when necessary.
  • It should be far enough away from the main headlights so as not to cause any glare.

Wiring the Lights

Once you’ve chosen a location, the next step is to drill a hole through the truck’s body. This will be where you run the wiring for the lights. Now it’s time to connect the wires.

  • First, connect the positive wire to the battery using a wire connector.
  • Then, connect the negative wire to a grounding point. This can be done by connecting it to a metal surface on the truck’s frame.

Testing the Lights

Now that you’ve connected the wires, it’s time to test the lights to ensure they’re working correctly. Once you’ve done that, you can enjoy the benefits of having auxiliary lights on your truck.

Do You Need a Relay for Auxiliary Lights?

Yes, using a relay for auxiliary lights is recommended. A relay helps ensure that the correct amount of power goes to the lights, preventing damage to your car’s battery or overloading the wires. Additionally, using a relay makes it easier to install auxiliary lights. Without a relay, you must be more cautious and check all connections more often.

Can You Wire Fog Lights to Your Headlights?

Wiring your fog lights to your headlights is possible but not recommended. Doing so may cause your headlights to blow a fuse, or the extra amperage draw may melt or burn the headlight wiring harness. If you intend to wield your fog lights to your headlights, use a relay so that the extra amperage draw does not damage your headlight circuit. Additionally, check your local laws to see any restrictions on using fog lights. In some states, fog lights can only be used in certain conditions, such as when weather reduces visibility.

How to Tap Into Headlight Wires

To tap into headlight wires:

  1. Locate the fuse box and identify the wire that powers the headlights.
  2. Use a wire cutter to splice it into the wire.
  3. After splicing it into the wire, run your new wire to wherever you need it to go.
  4. Use heat shrink tubing or electrical tape to secure your connections, which will help prevent shorts.

Tapping into headlight wires is simple but ensures a safe and reliable connection.

What Color is the Reverse Wire?

The color of the reverse wire varies depending on the make and model of the vehicle. However, in most cases, the reverse wire is red. The red wire passes the reverse signal to the front of the car, which is then connected to the camera. The camera end has a red and black wire connected to the reverse light and ground, respectively. The reverse wire may be another color, such as black or white. Regardless of color, the reverse wire serves the same purpose: activating the backup camera when the car is in reverse.

Wiring LED Light Bar Directly to Battery

While it’s possible to wire an LED light bar directly to your car battery, there are a few things you need to keep in mind. Car batteries are powerful enough to melt a wrench if it touches both terminals. A short LED bar or cable circuit could easily start a fire. Moreover, LED light bars draw a lot of power, which could strain the electrical system if wired directly to the battery. Therefore, it’s generally recommended to wire the light bar through a switch so that you can control the amount of power it’s drawing.

Using Relays Instead of Switches

Electrical relays are a more cost-effective and space-efficient alternative to switches. Relays use a smaller unit of electricity to turn circuits on and off, allowing manufacturers to save money and design smaller, more efficient equipment. Additionally, the smaller size of relays means that more functionality can be included in the same area. Therefore, relays have many advantages over switches and are a preferred option.


Wiring an LED light bar to your car battery can be done safely and efficiently. Still, it’s essential to consider the potential hazards and strain on the electrical system. Using a switch to control the power drawn by the light bar is generally recommended. Electrical relays offer a cost-effective and space-efficient alternative to switches. They can help manufacturers design smaller and more efficient equipment. By following these guidelines, you can easily and confidently wire auxiliary lights on your truck.

About the author, Laurence Perkins

Laurence Perkins is the passionate car enthusiast behind the blog My Auto Machine. With over a decade of experience in the automotive industry, Perkins has knowledge and experience with a wide range of car makes and models. His particular interests lie in performance and modification, and his blog covers these topics in-depth. In addition to his own blog, Perkins is a respected voice in the automotive community and writes for various automotive publications. His insights and opinions on cars are highly sought-after.