Trailer Wiring Diagram - 4, 5, 6, 7 Pin/Wire (with Brakes, Lights)

Hey, in this article we are going to see the Trailer Wiring Diagram and will discuss all the important things such as color codes, connection procedures, use of different types of connectors, etc. A trailer is a vehicle have not any body or structure it is just a structure with wheels and important accessories. So, after purchasing a new trailer we need to do it manually wiring in the trailer to place different types of lights, electric brakes, and other accessories. After completing it is time to connect with a tow vehicle and this required connector. This article not only helps to install new wiring for the trailer but it also helps to repair or find faults in the old one. Once you know how the wiring is done, which color code is used for which purpose, which type of connector we should use, or which size of wire we have to use, then you can easily understand and be able to do wiring-related work.

Basically, the four types of wiring are used that are explained below,

4 Pin/Wire/Way Trailer Wiring Diagram( with Lights)

Here, you can see the wiring diagram of trailer for 4 pin/wire/way.

Here, you can see a flat type 4 wire connector is used that has three pins and one socket. Generally, there are two types of connectors are available - flat type and cylindrical type. For a 4-wire connection, mostly the flat type connector is used. In a 4-wire connection following wires are used,

1. White color wire for grounding. It is connected to the metal chassis of the trailer. Also, all the white wires from each light and brakes or other accessories are also connected to the metal chassis. Also, note that the size of the wire should be a minimum of 16 gauge
2. Brown Color wire is used to supply all the normal marker lamps such as side markers, rear markers, and backside markers. It should have a minimum of 18 gauge
3. The green color is used to deliver power to the Rear Right lamp which is used for turning indication or stop indication.
4. The yellow color wire is used to deliver power to the rear left lamp which is used for the turning or stop indication. It also should have a minimum of 18 gauge.

5 Pin/Wire/Way Trailer Wiring Diagram( with Lights and Brake)

Here, you can see the wiring diagram of Trailer for 5 wire or 5 way

Here also you can see a fault-type five-pin connector is used that has four pins and one socket. For 5-way wiring, mostly the flat type connector is used. The 5-wire trailer connection is the same as the 4-wire connection just it has an additional connection for the electric braking system such as electric over the hydraulic system or any other type. Generally, a blue color wire has a minimum size of 18 gauge is used for the connection of the electrical braking system. Generally, the brake system is installed in, on, or under the trailer parts. You can see in the above diagram how the blue wire is going for the electrical braking system.

6 Pin/Wire/Way Trailer Wiring Diagram( with Lights, Brakes, Battery)

Here, you can see the wiring diagram of Trailer for 6 Waye or 6 wire connections.

For the 6-wire connection, mostly the cylindrical connector is used to connect the trailer to the tow vehicle. In this 6-wire connection following functions are available,

1. White for Ground Connection
2. Green for the rear right lamp
3. Yellow for the rear left lamp
4. Purple for marker lights
5. Blue for the braking system
6. Red or black wire for battery charging or other accessories.

Remember that here we have shown the red color wire only but black color wire can be used instead of the red color wire. And this wire should have a minimum size of 12 gauge. This generally connected to the battery of the tow vehicle mostly is carrying 12V DC but in some cases 24V DC also. And another terminal is to be connected to the battery charger of the trailer or can be used for the power supply to other accessories.

7 Pin/Wire/Way Trailer Wiring Diagram( with Lights, Brakes, Battery, and Backup)

Here, you can see the wiring diagram of Trailer for 7 wire or 7-way connection.

Here, for the 7-wire connection also, the cylindrical type connector is used to connect the trailer to the tow vehicle. The 7-way system has the same function as the 6-way system, just it has an additional connection for backup lights or hydraulic coupler. Generally, the 7th wire is in purple color and has a minimum size of 12 gauge.

Trailer Wiring Color Codes

Here, you can see the wire size and color codes for trailer wiring.

You can see,

• Ground Connection is used by white color
• The Rear Right lamp connection is used by green color
• The rear left lamp connection is used by yellow color
• Markers lamp connection is used by purple color
• The brake connection is used by blue color
• Battery connection is used by Red or Black Color
• The backup power system is used by the purple color but sometimes other colors are also used.

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