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Trailer wiring is an important aspect of towing. It provides power to the lights and brakes on a trailer, allowing it to be seen by other drivers and safely brought to a stop. There are different types of trailer wiring, with 4 wire trailer wire being one of the most common.

Types of 4 Wire Trailer Wire

There are two main types of 4 wire trailer wire: bonded wire and non-bonded wire. Bonded wire has the four wires (ground, running lights, left turn/brake, right turn/brake) joined together along their length. Non-bonded wire has separate wires that need to be connected to each other and to the trailer.

Color Coding for 4 Wire Trailer Wire

4 wire trailer wire is color-coded for easy identification and installation. The wires are:

Wire Color Function
Brown Running Lights
Yellow Left Turn/Brake
Green Right Turn/Brake
White Ground

Installation of 4 Wire Trailer Wire

Installing 4 wire trailer wire is a straightforward process, but it does require some basic knowledge of electrical wiring. Here are the steps to follow:

  1. Make sure the trailer wiring matches the towing vehicle’s wiring.
  2. Disconnect the trailer from the towing vehicle.
  3. Strip the ends of the wires on the trailer and the towing vehicle.
  4. Connect the wires according to their function (running lights, left turn/brake, right turn/brake, ground).
  5. Test the trailer lights to make sure they are working properly.
  6. Secure any loose wires with zip ties or other fasteners.
  7. Reconnect the trailer to the towing vehicle.

Maintenance of 4 Wire Trailer Wire

Maintaining 4 wire trailer wire is important to ensure safe and reliable towing. Here are some tips:

  • Regularly check the wires for any signs of damage, such as cracks or fraying.
  • Clean the connections with electrical contact cleaner and a wire brush to remove any corrosion.
  • Use dielectric grease on the connections to prevent corrosion.
  • Replace any damaged wires or connections immediately.


4 wire trailer wire is an essential component of towing. Understanding the types of wire, color coding, installation process, and maintenance requirements can help ensure safe and trouble-free towing. Follow these guidelines to enjoy a stress-free towing experience!

Published On: 2023年6月13日Categories: ,