How to Install Car Trailer Wiring Diagram?

Nearly every trailer requires a connection to the towing vehicle’s electrical system through trailer wiring. When it comes to wiring your trailer, you might be wondering, how exactly should these wires be connected? By reading this article, you will learn the specific steps for wiring your trailer.

Trailer Wiring Diagrams

Trailer Wiring Connectors usually come with 4 to 7 pins, offering a range of options for transmitting lighting power and other auxiliary functions. The more functions a trailer has, like trailer brake controllers or backup lights, the more pins it will require. The diagram below simplifies the understanding of what each colored wire represents.

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Trailer Wiring Diagrams

4-Pin Trailer Wiring Diagram

This is the most basic type of trailer wiring connector. Following standard wiring practices is crucial for safety. Incorrect color connections may lead to malfunctioning or mismatched tail lights, causing confusion while driving. Refer to the diagram for proper wire connections.

4-Pin Trailer Wiring Diagram

Green: Right turn / brakes

Yellow: Left turn / brakes

Brown: Taillights

White: Ground

5-Pin Trailer Wiring Diagram

Compared to the 4-pin trailer wiring, the 5-pin version includes an additional blue wire for the reverse lights. However, not all trailers have reverse lights; it’s advisable to confirm with the seller.

5-Pin Trailer Wiring Diagram

Blue: Reverse lights

Yellow: Left turn / brakes

Green: Right turn / brakes

Brown: Taillights

White: Ground

6-Pin Trailer Wiring Diagram

The 6-pin trailer wiring includes two additional functions over the 4-pin: a wire for the trailer brake controller and another for a 12V auxiliary power supply. This wiring style is commonly found in gooseneck trailers.

6-Pin Trailer Wiring Diagram

Black: +12 volt

Blue: Reverse lights

Yellow: Left turn / brakes

Green: Right turn / brakes

Brown: Taillights

White: Ground

7-Pin Trailer Wiring Diagram

There are two types of 7-pin trailer connectors: one is round and the other is an RV blade plug. Different colors represent different functions, as detailed in the diagram below:

Round 7-Pin Wiring Diagram

Round 7-Pin Wiring Diagram

Red: Auxiliary power

Black: Reverse lights

Blue: Electric brakes

Yellow: Left turn / brakes

Green: Right turn / brakes

Brown: Taillights

White: Ground

RV Blade 7-Pin Trailer Wiring Diagram - SAE

Grey: Reverse lights

Orange: +12 volt

Blue: Electric brakes

Yellow: Left turn / brakes

Green: Right turn / brakes

Brown: Taillights

White: Ground

If you are looking to purchase a trailer, feel free to contact Three Horses Trailer. We are committed to providing you with top-notch service.

Depending on your region, we will equip your trailer with the appropriate wiring connector. Even if you lose your electrical connection diagram, don’t hesitate to reach out to us. We are here to assist you and resolve any issues you may have.

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