4 Way Round Trailer Plug Wiring Diagram

If you are planning to tow a trailer with your car or truck, then you need to have a proper wiring setup. The wiring setup includes connecting the trailer to the vehicle’s electrical system. One of the most commonly used trailer connectors is the 4-way round trailer plug, which is designed for trailers with brakes and lights. In this article, we will discuss the 4 way round trailer plug wiring diagram, including tables and FAQs.

What is a 4 Way Round Trailer Plug?

A 4 way round trailer plug is a connector that is used to connect a trailer’s electrical system to the vehicle’s electrical system. It is called a “4 way” because it has four pins or connections, which are used to connect the trailer’s brake lights, tail lights, and turn signals. The 4-way round trailer plug is compatible with most cars and trucks that have a towing package, and it is also commonly used for small utility trailers, boat trailers, and horse trailers.

Pin Placement

The 4-way round trailer plug has four pins or connections. Each pin has a specific function and placement:

Pin Function Color
1 Ground White
2 Tail lights Brown
3 Left turn signal Yellow
4 Right turn signal Green

Note: The pin placement may vary depending on the manufacturer, so it is always recommended to check the manufacturer’s wiring diagram.

Wiring the 4 Way Round Trailer Plug

Wiring the 4 way round trailer plug is a straightforward process. Here are the steps:

  1. Disconnect the vehicle’s battery to avoid any electrical accidents.
  2. Identify the wires on the trailer connector and trim the ends if needed.
  3. Strip the insulation from the wires about 1/2 inch from the end.
  4. Insert the wires into the corresponding pins on the trailer plug.
  5. Crimp the wires using a crimping tool.
  6. Test the trailer’s lights and brakes to ensure they are working correctly.
  7. Reconnect the vehicle’s battery.

FAQ

What is the wire color code for a 4-way trailer plug?

The wire color code for a 4-way trailer plug is as follows:

Pin Function Color
1 Ground White
2 Tail lights Brown
3 Left turn signal Yellow
4 Right turn signal Green

What is the maximum capacity of a trailer that can be used with a 4-way trailer plug?

The maximum capacity of a trailer that can be used with a 4-way trailer plug depends on the towing capacity of the vehicle. It is always recommended to check the vehicle’s owner’s manual for the maximum towing capacity and the manufacturer’s recommendation for the trailer’s weight.

What are the common problems with a 4-way trailer plug?

The common problems with a 4-way trailer plug include loose connections, broken wires, and corroded pins. These problems can cause the trailer’s lights and brakes to malfunction, which can be dangerous while towing. Regular maintenance and inspection of the trailer plug can help prevent these problems.

How do I troubleshoot a 4-way trailer plug?

To troubleshoot a 4-way trailer plug, you can use a voltmeter to check the voltage at each pin. If there is no voltage, check the wiring and connections for any loose or broken wires. You can also use a test light to check for any short circuits. If you are unsure about how to troubleshoot the trailer plug, it is always recommended to seek professional help.

Can I convert a 4-way trailer plug to a 7-way trailer plug?

Yes, you can convert a 4-way trailer plug to a 7-way trailer plug using an adapter. The adapter will have a 4-way plug on one end and a 7-way plug on the other end, allowing you to connect the trailer’s brakes, battery, and other accessories. It is always recommended to check the manufacturer’s recommendation before converting the trailer plug.

Conclusion

The 4 way round trailer plug is a commonly used connector for trailers with brakes and lights. It is a simple and easy-to-wire setup that can be done by anyone with basic electrical knowledge. By following the wiring diagram and the pin placement, you can ensure that the trailer’s lights and brakes are working properly. Regular maintenance and inspection of the trailer plug can help prevent any problems while towing. If you have any further questions or concerns, it is always recommended to seek professional help.