How to Wire Trailer Lights

By: Date: 17 December 2023

Are you preparing for an off-road adventure with your camper trailer and want to ensure your trailer lights are wired correctly? 

Trailer lights themselves are must-haves when it comes to 4×4 accessories, and knowing how to wire them is crucial for safety and compliance with road regulations. 

In this guide, we’ll take you through the process of wiring trailer lights for your off-road camper trailer or caravan.

Understanding Trailer Light Wiring Basics

Trailer light wiring may seem intimidating with its multitude of wires and connectors, but we’re here to help. 

Trailer lights typically require functions like brake lights, turn signals, and tail lights. Some trailers may also need side markers, running lights, or electric brakes. 

Knowing the various wire colours and functions is key to ensuring a safe towing experience.

Related: How to Choose the Right Wheel Bearing For Your Trailer

The Ideal Wiring Setup for Your Off-Road Camper Trailer

Wire colours diagram

Credit: Mechanical Elements

For lighter-duty trailers without brakes, a common choice is the 4-pin flat connector. 

This setup includes wires for ground, tail lights, left turn signal, and right turn signal. It’s suitable for consumer-type trailers like small utility trailers and off-road trailers.

Trailers with electric brakes typically require a 5-pin flat connector. In addition to the functions of the 4-pin setup, the 5th wire (blue) is used for electric brakes control.

For trailers with complex electrical needs, like auxiliary power and back-up lights, a 7-pin connector is recommended. This style is common for bigger trailers like RVs and offers additional functionality.

Step-by-Step Guide: How to Wire Your Trailer Lights

Materials Needed:

  • Crimp Connectors
  • Cable Ties
  • Electrical Tape
  • New Lights and/or Wiring
  • Heat Shrink

Tools Required:

  • Basic Mechanic’s Tools
  • Wire Strippers
  • Terminal Crimper
  • Heat Gun

Wiring Steps:

  1. Connect Trailer: Start by connecting your trailer to the tow vehicle for a stable workspace.
  2. Run New Wiring: Take the trailer harness and run it down one side of the trailer, either through the chassis rail or attached to the trailer frame with cable ties.
  3. Trim Excess Wires: Trim any unnecessary wiring from the trailer harness.
  4. Strip Insulation: Strip insulation from all wires in the trailer harness.
  5. Mount New Trailer Lights: Mount the lights to each side of the trailer, ensuring they match the old lights’ positions.
  6. Connect Wiring: Connect the wires from the lights to the new wiring, sealing each connection with heat shrink.
  7. Test: Connect the trailer plug to the tow vehicle socket and test the lights.
  8. Finalise the Wiring: Seal all connections with electrical tape to protect them from moisture and dirt.

Globe Lights vs LED Lights: Which Type is Best For You?

Globe light and LED light

Globe Lights

Globe lights, also known as incandescent lights, have been the standard vehicle light choice for many years. They emit a warm, familiar glow and are relatively inexpensive to purchase. 

Globe lights are readily available and easy to replace when needed. However, they have several drawbacks compared to LED lights. 

Globe lights consume more power, meaning they drain your battery faster, which is particularly important when off-grid. 

They also have a shorter lifespan and are more prone to breaking due to their delicate filaments. 

Globe lights can also generate more heat, which can be a concern in enclosed spaces or during hot weather.

LED Lights

LED lights, on the other hand, offer numerous benefits that make them a popular choice for off-road camper trailers. 

LED lights are highly energy-efficient, consuming significantly less power than globe lights. This means they put less strain on your battery and can extend your battery life, making them ideal for off-grid adventures. 

LED lights also have a much longer lifespan, lasting up to 50 times longer than traditional globe lights. They’re also more durable and shock-resistant, making them better suited for rugged off-road conditions. 

LED lights produce little to no heat, reducing the risk of fire hazards and making them safer to use in confined spaces.

Wiring Trailer Lights: Essentials for Your Off-Road Adventures

Wiring trailer lights for your off-road camper trailer may seem daunting, but with the right guidance, you can set up your trailer for a safe towing experience. 

By following wiring standards and using appropriate connectors, you can ensure your trailer lights function properly, enhancing visibility and safety on the road.
Further reading: Looking for more must-have gear for your next off-road adventure? Master your trips with our Jerry Cans & Fuel Planning Guide