Wiring Diagram for Trailer Lights 4 Pin

If you’re planning on towing a trailer, it’s important to have proper lighting installed. Trailer lights not only help you see in the dark, but they also help other drivers see you on the road. In this article, we’ll be going over everything you need to know about wiring trailer lights with a 4 pin connector.

What is a 4 Pin Connector?

A 4 pin connector is the most common type of trailer wiring available. It consists of four wires; a ground wire, a left turn/brake wire, a right turn/brake wire, and a taillight wire. The ground wire ensures that the electrical system is properly grounded, while the turn/brake and taillight wires control the corresponding lights on the trailer.

One thing to note is that 4 pin connectors are only capable of supporting basic lighting functions. If you need to add additional features like electric brakes, you’ll need to upgrade to a 7 pin connector.

Materials Needed

Before getting started, you’ll need to gather a few materials:

Materials Quantity
4 pin connector 1
Wire cutters/strippers 1 pair
Electrical tape 1 roll
Heat shrink tubing 1 pack
Crimping tool 1
Zip ties 1 pack

Step-by-Step Instructions

Step 1: Disconnect Battery

Before beginning any electrical work, it’s important to disconnect the negative battery cable to prevent any accidental short circuits.

Step 2: Locate Trailer Wiring

Locate the trailer’s wiring harness and inspect it for any damage or corrosion. Replace any damaged wiring before continuing.

Step 3: Strip Wires

Strip approximately 1/2 inch of insulation off of the end of each wire. Be careful not to strip too much, as it can cause the wire to break or short circuit.

Step 4: Connect Wires

Connect the wires on the trailer to the corresponding wires on the 4 pin connector. The color codes for the wires are as follows:

Wire Color Function
White Ground
Brown Taillight
Yellow Left Turn/Brake
Green Right Turn/Brake

Secure the connections with the crimping tool, and then wrap each connection with electrical tape to prevent any moisture from seeping in.

Step 5: Test the Lights

Reconnect the negative battery cable and test the trailer lights to make sure everything is working correctly. If anything is not working, double-check your connections and wiring before trying again.

Frequently Asked Questions

Q: Do I need a special tool to crimp the wires?

A: Yes, you will need a crimping tool to ensure a secure and long-lasting connection.

Q: Can I use electrical tape instead of heat shrink tubing?

A: While electrical tape can be used, heat shrink tubing provides a stronger and more durable seal that is better at preventing moisture from entering the wire connections.

Q: What if my trailer has more than four wires?

A: If your trailer has additional features like electric brakes or reverse lights, you’ll need to upgrade to a 7 pin connector.

Q: Can I tow my trailer without working lights?

A: No, it is illegal to tow a trailer without functioning lights. Not only can it result in a traffic violation, but it also puts you and other drivers on the road in danger.