Flat 4 trailer wiring is an essential part of any trailer towing operation. It is one of the most common wiring configurations for trailers, and is easy to install and maintain. If you are new to flat 4 trailer wiring, or just need a refresher, this article will provide you with all the information you need to know.
What is Flat 4 Trailer Wiring?
Flat 4 trailer wiring is a wiring configuration that uses four wires to connect a trailer’s lighting system to the towing vehicle’s lighting system. The four wires are typically color-coded as follows:
| Wire Color | Function |
| Brown | Taillights |
| Yellow | Left Turn and Brake Lights |
| Green | Right Turn and Brake Lights |
| White | Ground |
The white wire is the ground wire, which connects the trailer’s metal frame to the towing vehicle’s frame. The brown wire controls the trailer’s taillights, while the yellow and green wires control the left and right turn and brake lights, respectively.
In addition to these four wires, some flat 4 trailer wiring configurations may include a fifth wire for auxiliary power or electric brakes. However, this is not always the case.
How to Wire Flat 4 Trailer Wiring?
Wiring flat 4 trailer wiring is a relatively simple process that can be done in a few steps:
Step 1: Gather Supplies
The first step to wiring flat 4 trailer wiring is to gather all the necessary supplies. These supplies include:
- Flat 4 trailer wiring kit
- Wire stripper
- Wire cutter
- Electrical tape
Step 2: Strip the Wires
After gathering the necessary supplies, strip about 1/2 inch of insulation off the ends of each wire using a wire stripper.
Step 3: Connect the Wires
Next, connect the wires as follows:
- Brown wire to the taillights
- Yellow wire to the left turn and brake lights
- Green wire to the right turn and brake lights
- White wire to the ground
Secure each connection with electrical tape.
Step 4: Test the Wiring
After connecting the wires, test the flat 4 trailer wiring by plugging the trailer connector into the towing vehicle’s connector and testing each light function.
Flat 4 Trailer Wiring Diagram FAQs
What is the difference between flat 4 and round 4 trailer wiring?
The primary difference between flat 4 and round 4 trailer wiring is the shape of the connector. Flat 4 connectors have four pins arranged in a flat configuration, while round 4 connectors have four pins arranged in a circular configuration. Both wiring configurations are commonly used and provide similar functionality.
Can I use flat 4 trailer wiring for electric brakes?
Flat 4 trailer wiring may include a fifth wire for electric brakes, but it is not recommended for this purpose. Electric brakes require a separate brake controller and wiring configuration, which is typically more involved than flat 4 wiring.
What if I have a trailer with more than four lights?
If you have a trailer with more than four lights, you may need to use a different wiring configuration, such as flat 5 or round 7 wiring. These configurations provide additional wires for additional light functions.
Can I install flat 4 trailer wiring myself?
Yes, flat 4 trailer wiring is a simple wiring configuration that can be installed by most do-it-yourselfers. Just be sure to follow the manufacturer’s instructions and use proper wiring techniques to ensure a safe and reliable connection.
Is flat 4 trailer wiring compatible with all towing vehicles?
Flat 4 trailer wiring is compatible with most towing vehicles that have a standard 4-pin connector. However, some vehicles may require an adapter to convert the wiring configuration to match the towing vehicle’s connector.
Conclusion
Flat 4 trailer wiring is a simple and reliable wiring configuration for trailers that is easy to install and maintain. Whether you are new to flat 4 trailer wiring or just need a refresher, the information provided in this article should help you understand how it works and how to install it properly.
