The traditional 7-way RV blade format is typically used on 5th wheel trailers, travel trailers and campers. The trailer wiring colors for this configuration are different than those on the SAE configuration.

Note: The ground wire color for a 4-flat plug is white and should be properly grounded at the trailer tongue. Read the complete rewiring guide for more.

If custom wiring is not available for your particular make and model, a taillight converter may be required to equip your vehicle with the proper trailer light wiring connection.

Trailers are equipped with different plug types based on their electrical components. The chart below provides examples of common trailers and the types of plugs they typically use.

Connector Pins Male

If you need assistance with your trailer’s 4-wire connection, check out our comprehensive Ultimate Guide to 4-Wire Trailer Connectors for additional information.

The 7-way round trailer plug is to be distinguished from 7-way RV blade plugs. The wiring connections and placement are different.

Connector pins

• Green Taillights• Red Left turn / brakesº White Ground• Blue Electric brakes• Brown Right turn / brakes• Black +12 volt• Yellow Reverse lights

Following the standard method for wiring a trailer connector is vital to the safety of your vehicle while towing. Connecting the wrong color wires will result in mismatched taillight functions and confusion on the road.

PinConnector Socket

If the trailer plug wiring on your vehicle or trailer is damaged or not working correctly, you can replace the connector with a CURT splice-in plug or socket.

Custom wiring is the ideal solution for installing trailer light wiring on your vehicle. A custom wiring harness or 'T-connector' is a vehicle-specific harness that plugs in without any spicing required and provides a standard connector output, such as a 4-way flat.

Electricalpinconnector types

• Green Taillights• Red Left turn / brakesº White Ground• Blue Electric brakes• Brown Right turn / brakes• Black +12 volt• Yellow Reverse lights

Like a T-connector, an original equipment wiring harness plugs into the USCAR socket without any cutting, splicing or soldering required, and it provides a standard trailer wiring output, such as a 4-way flat or 7-way RV blade.

While some vehicles may not be equipped with a standard trailer wiring connector, they may have a special socket specifically intended for installing wiring, provided by the vehicle manufacturer. A custom wiring connector uses a single plug to plug into this factory socket and provide a standard trailer wiring connector.

If your vehicle is not equipped with working trailer wiring, there are a number of different solutions to provide the perfect fit for your specific vehicle. Complete with a color coded trailer wiring diagram of each plug type, this guide walks through each available solution, including custom wiring, splice-in wiring and replacement wiring.

A taillight converter or electrical converter splices into your vehicle and provides a standard trailer plug wiring connector, typically a 4-way flat. The converter converts the vehicle's complex wiring system to be compatible with your trailer's simple wiring system. To learn more about vehicle wiring systems, check out our vehicle wiring systems guide.

º White Ground• Brown Taillights• Green Right turn / brakes• Red Auxiliary power• Yellow Left turn / brakes• Black Reverse lights• Blue Electric brakes

Note: The ground wire color on all trailer plug types is always white.  Other colors vary in function, depending on the configuration.

7-pin trailer wiring is one of the most popular wiring configruations, particularly the traditional configuration versus the SAE J2863.

Plugs (trailer side) and sockets (vehicle side) are available in all standard formats and can be spliced into your existing trailer plug wiring. Find the trailer light wiring diagram below that corresponds to your existing configuration.

WirePinConnectors Kit

The SAE J2863 7-way RV blade format is typically used on gooseneck trailers, utility trailers, cargo trailers and equipment trailers.

The SAE configuration of a 7-way RV blade plug should not be confused with the traditional configuration. Different wire colors are used for different functions.

Connector Pins Female

º White Ground• Brown Taillights• Green Right turn / brakes• Red Auxiliary power• Yellow Left turn / brakes• Black Reverse lights• Blue Electric brakes

Note: Not all trailers are equipped with reverse lights (yellow wire). The position of this wire may vary for your own specific setup.

• Brown Taillights• Yellow Left turn / brakesº White Ground• Blue Electric brakes• Green Right turn / brakes• Orange +12 volt• Grey Reverse lights

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• Brown Taillights• Yellow Left turn / brakesº White Ground• Blue Electric brakes• Green Right turn / brakes• Orange +12 volt• Grey Reverse lights

Any vehicle towing a trailer requires a trailer wiring harness to safely connect the taillights, turn signals, brake lights and other necessary electrical systems.

All CURT custom wiring comes with the exact components needed for a complete installation on the vehicle, including vehicle-specific plugs and an electrical converter, if needed.

Learn more about different trailer types here. Refer to the wiring diagrams above for functions of trailer wiring colors.

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A custom wiring harness has multiple plugs that are used to 'T' into the vehicle's taillight assembly, drawing power directly from the taillights or from a direct battery connection and providing a standard trailer light wiring connector. While custom wiring harnesses usually require two or more connection points, splicing and soldering are still not needed.

6-pin trailer wiring introduces two new functions, a wire for connecting trailer brakes and a wire for +12-volt auxiliary power.

Another type of custom wiring is original-equipment (OE) wiring or USCAR wiring. Select vehicles come with a standardized USCAR socket that provides a connection point for a CURT OE wiring harness.