Understanding the Color Code for Trailer Wires

Trailer wiring is an essential part of any hauling job, as it allows drivers to connect trailers to their cars. Without the right wiring in place, drivers could be facing a dangerous situation on the road. To prevent this, trailer wiring connections are made with specific colors to indicate which wire goes where. By understanding the color code for trailer wires, drivers are able to ensure that their trailer is properly wired.

The most common trailer wire color code refers to the four-wire system, which includes white, yellow, blue, and green. It’s important to note that the white wire is actually the ground wire, while yellow, blue, and green are used for functioning. Additionally, there is an optional fifth wire that can be used as an auxiliary power source. All of these wires come in black or brown insulation for easy identification.

White - Ground Wire

The white wire is what’s known as the ground wire, and it’s the wire that keeps everything powered from the source. The ground wire is connected to the frame of the trailer and the battery, which helps create a safe connection that allows for normal function. It also functions as a backup should the other wiring become faulty.

Yellow - Left Hand Turn Indicator

The yellow wire is typically used as the left hand turn indicator, which means it signals when the driver is turning left. This wire will also illuminate any taillights or headlights for safer driving experience. The signal should be strong enough to be visible from far away, and if it isn’t it may be a sign that the connection is loose or otherwise not properly connected.

Blue - Right Hand Turn Indicator

In contrast to the yellow wire, the blue wire serves as the right hand turn indicator, signaling when the driver wants to turn right. This wire will also illuminate any taillights or headlights, and it should be just as visible as its yellow counterpart. Again, if the signal isn’t visible it may be a sign that the connection is loose or otherwise not properly connected.

Green - Tail Lights & Stop Lights

The green wire is responsible for powering the trailer’s tail lights and stop lights. This ensures that when the brake pedal is pushed, the trailer’s stop lights will illuminate and alert oncoming drivers. The green wire should be the same strength as the other wires, and it should be connected to the reverse lights for proper operation.

Optional Fifth Wire

The fifth wire, if included, is typically used as an auxiliary power source. This wire can be used to provide power to any accessories that need it, such as a winch or electric brakes. This wire is often connected either to the trailer’s brakes or to the battery and should be kept secure at all times.

By knowing the trailer wire color code, drivers can ensure that their trailer has a safe and secure connection. This makes it easier to navigate the road safely and reduces the risk of an issue while the trailer is in use. Additionally, it’s important to regularly check the connections to make sure they’re still secure, as loose connections can cause dangerous situations down the line.

International Standard Trailer Wiring Kea Trailers