Choosing the right trailer connector is important because the connector determines which electrical functions can be communicated between your tow vehicle and trailer.
The most common trailer connectors you’ll run into are 4-way, 5-way, 6-way, and 7-way connectors. For basic utility trailers, a 4-way connector is often enough. Larger trailers and equipment trailers commonly use a 7-way connector because it provides additional circuits for functions such as electric brakes and auxiliary power.
4-Way Flat
The 4-way flat connector is one of the simplest trailer wiring connections. It typically handles:
- Ground
- Left turn signal
- Right turn signal
- Tail/running lights
It’s commonly found on smaller utility trailers, small boat trailers, and lightweight trailers without electric brakes.
5-Way Flat
A 5-way connector adds another circuit to the basic four lighting functions. That additional circuit is commonly used for a reverse or surge-brake function, depending on the trailer’s setup.
This makes a 5-way useful for certain boat trailers and other applications where an additional electrical function is needed.
6-Way Connectors
Six-way connectors are available in both round and other configurations and can be used for trailers requiring additional circuits beyond basic lighting.
They’re less common than 4-way and 7-way connectors on many modern utility and equipment trailers, but you may still encounter them on older or specialized setups.
7-Way RV-Style Connector
The 7-way connector is one of the most common choices for larger trailers and equipment trailers.
A typical 7-way connection can provide circuits for:
- Ground
- Tail/running lights
- Left turn/brake
- Right turn/brake
- Electric trailer brakes
- Auxiliary 12-volt power
- Reverse/auxiliary function
This makes the 7-way particularly useful for equipment trailers, enclosed trailers, travel trailers, and trailers equipped with electric brakes.
Which One Do You Need?
For a small utility trailer with basic lighting, a 4-way connector may be all you need.
For a larger trailer with electric brakes, auxiliary power, or additional electrical equipment, a 7-way connector is generally the more appropriate setup.
The important thing is to match the connector to the electrical equipment actually installed on your trailer and make sure the tow vehicle is equipped to support those functions.
💡 Wayman’s Tip
If you’re replacing a trailer connector, take a picture of the existing wiring before cutting anything loose. Then verify each circuit with a wiring diagram and test light or multimeter. That simple step can save a lot of troubleshooting later.