If you own a trailer, it’s essential to know how to wire it properly. One of the most common trailer wiring systems is the 4 flat wiring system. In this guide, we’ll provide you with a complete guide on a 4 flat trailer wiring diagram to help you understand and wire your trailer correctly.
What Is a 4 Flat Wiring System?
A 4 flat wiring system is a type of electrical connector used to connect a trailer to the towing vehicle. It consists of four wires that provide power to the trailer’s brake lights, turn signals, and taillights. It’s called “4 flat” because the wires are flat and have a square shape.
The four wires in a 4 flat wiring system include:
| Wire | Color | Function |
|---|---|---|
| White | Ground | Connects to the towing vehicle’s chassis |
| Brown | Taillights | Provides power to the trailer’s taillights |
| Yellow | Left turn/brake | Provides power to the trailer’s left turn signal and brake light |
| Green | Right turn/brake | Provides power to the trailer’s right turn signal and brake light |
Understanding the color codes and functions of each wire is crucial when wiring your trailer.
How to Wire a 4 Flat Wiring System
Wiring a 4 flat wiring system involves connecting the four wires to the trailer’s electrical system and the towing vehicle’s electrical system. Here’s how to do it:
Step 1: Install the Trailer Connector
The first step in wiring a 4 flat wiring system is to install the trailer connector. The connector is where you’ll connect the trailer’s wires to the towing vehicle’s electrical system. You can buy a trailer connector kit that includes the connector, wires, and mounting hardware.
Step 2: Connect the White Wire
The white wire is the ground wire and should be connected to the towing vehicle’s chassis. Look for a spot on the chassis that is bare metal and use a self-tapping screw to secure the wire.
Step 3: Connect the Brown Wire
The brown wire connects to the trailer’s taillights. Locate the taillight wires in the trailer’s electrical system and splice the brown wire to them using a butt connector.
Step 4: Connect the Yellow and Green Wires
The yellow and green wires connect to the trailer’s left and right turn signals and brake lights. Find the wires in the trailer’s electrical system and splice the yellow wire to the left turn signal wires and the green wire to the right turn signal wires using butt connectors.
Step 5: Test the Wiring
After connecting all the wires, test the wiring by turning on the towing vehicle’s headlights, taillights, left and right turn signals, and brake lights. Ensure that all the trailer lights are working correctly.
FAQs
What gauge wire should I use for a 4 flat wiring system?
You should use 16-gauge wire for a 4 flat wiring system. It’s thick enough to carry the required power and thin enough to be easy to work with.
Do I need to use a fuse for a 4 flat wiring system?
Yes, you should use a fuse to protect your trailer’s electrical system in case of a short circuit. Use a 10-amp fuse for a 4 flat wiring system.
What if my trailer has more than four lights?
If your trailer has more than four lights, you can use a 5 flat, 6 flat, or 7 flat wiring system. Consult the wiring diagram for the specific system you’re using to ensure you wire it correctly.
Can I wire a 4 flat wiring system myself?
Yes, you can wire a 4 flat wiring system yourself if you have basic electrical knowledge. However, if you’re not confident, it’s best to seek professional help.
What’s the maximum amperage a 4 flat wiring system can handle?
A 4 flat wiring system can handle up to 7.5 amps per circuit. Ensure you don’t exceed this limit when wiring your trailer.
Conclusion
Wiring a 4 flat trailer system is an essential skill for anyone who owns a trailer. By following the steps outlined in this guide and understanding the color codes and functions of each wire, you’ll be able to wire your trailer safely and correctly. Remember to test your wiring after installation and seek professional help if you’re not confident in your ability.
