Having a reliable wiring diagram to help you understand and troubleshoot the 4-wire trailer wiring system is essential for any DIYer. The 4-wire system is the most common and is used for most trailers with brakes. This system has four wires, colored white, yellow, green and brown, and each wire is responsible for a different function.
White Wire
The white wire is the ground wire and is used to ground the trailer. It must be connected to the trailer frame and to the vehicle frame. This is done to prevent an electrical short and also to protect the wiring from corrosion.
Yellow Wire
The yellow wire is the left turn signal and brake light. This wire is connected to the left turn signal and brake light switch in the vehicle and is used to activate the trailer turn signal and brake lights.
Green Wire
The green wire is the right turn signal and brake light. This wire is connected to the right turn signal and brake light switch in the vehicle, and is used to activate the trailer turn signal and brake lights.
Brown Wire
The brown wire is the running light circuit. This wire is connected to the running light switch in the vehicle and is used to activate the trailer running lights.
Troubleshooting Tips
Troubleshooting a 4-wire trailer wiring system can be tricky, but with a few tips, it doesn’t have to be. First, make sure all the trailer wiring connections are secure and that the connections are not corroded. Next, check the fuse in the vehicle and make sure it is functioning properly. Finally, use a multimeter to check for voltage at the trailer connections.
Conclusion
Having a reliable 4-wire trailer wiring diagram can be a big help when troubleshooting wiring problems. Knowing which wire is responsible for each function makes it easier to identify and repair any problems with the wiring system. With these tips and a little patience, you’ll be able to get your trailer back on the road in no time.
