How To Wire A 4 Pin Trailer Connector To A 7 Pin Connector

May 09, 2021 3 min read

With new advancements and technology, there is a lot of competition in the world ofsolder connectors. There are numerous connectors, and each comes with unique features. But, when it comes to connectors and adapters of heavy machinery, there is a good variety.

From 4 to 7 pins; and adapters with extra wires; you will get everything. There are a lot of adapters that connect to hard wires and then to thetrailer. However, there is always a risk of blown-fuse and wiring issues. To learn how to connect your trailer and your vehicle, so this way your trailer should get the safety equipment fully powered and ready to work, like running lights, left turn signal, right turn signal, brake lights and so on. Keep on reading about how to wire a 4 pin trailer connector to a 7 pin connector

What is a pin trailer connector?

To safely connect the turn signals, brake lights, and electrical wiring; a trailer requires a trailer connector to protect the wires. The trailer adapter converts a tow vehicle and other wiring connections to a 7 pole wiring connector for trailers with hydraulic brakes. 

What is a 7 pin connector?

A 7 pin connector is a simple device and is more efficient, it has 3 more functions than compared to a 4 pin connector version. Not only does it handle the same tasks as the 4 pin, it comes with the ability to run the trailer’s 12-volt system, reverse lights and electric brakes. 

Not to mention, the 7-pin connector can also handle running lights, left and right turn signals, and brake lights. 

(You may not need to use a 7 pin connector if your vehicle already has a 4 pin installed underneath the bumper.)

What does the 7 pin connector do?

The 7 pin connector operates the most lights on your trailer. The right and left turning signals, reverse lights, aux power, brake lights, taillights and the electric brake.

Each light has its own color-coded wire so you need to make sure you connect the right colors to the right function. Your owner’s manual should help you with which wire goes to which wire.

How to wire a 4 pin trailer connector to a 7 pin connector?

Making a connection of a 4 pin trailer connector to a 7 pin connector is not difficult. However, you may have some experience in electrical power connections; as it’s a bit tricky.

  • Cut the connection 
  • Cut the connection of the 4-pin connector off the harness. There are color codes at each tail light; note the harness color codes. Both the taillights must have a common color. 

    However, the left and right turn signal lights have different colors. There are a total of three colors in the wiring harness. 

  • Test the 7 pin connector 
  • Do a test light with the 7-pin connector. Turn on the vehicle tail lights and note the location of the pin. 

    Now, do the same with both left and right turn signals. Observe the location of the ground wire and follow the wire to the body of the ground. 

  • Crimp the connector 
  • Crimp the connector and then plug the connector into the towing vehicle. Test run each circuit for any errors.

  • Make a safe wiring 
  • With the help of electrical tape, wrap the exposed wires and make a wiring harness. Make sure that there are no spliced wires; as they can lead to electrical damages. You can learn how to make a safe wiring connection reading thisarticle

    Making a connection of a 4 pin connector to a 7 pin connector or a trailer system is not difficult. However, it demands patience and concentration. We would recommend you to take some expert advice if you know nothing aboutconnectors and trailer systems. 


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