How to Wire a 6-Pin to 7-Pin Trailer

by Bob White

Many different harness types are used to connect tow vehicles' power sources to the electrical wiring on trailers. The difference between a 6-pin system and a 7-pin is that the 7-pin has a connection for backup lights. What systems are required by law for your trailer depends on where you live. These state laws are listed in the resource section below. If the loss of the backup lights doesn't present a problem, making the 6-pin connection is easy with the right adapter.

Determine if the vehicle's 6-pin connector is round or square.

Look at the trailer's 7-pin electrical harness and determine if the electrical connections are flat or round. Flat connections have wide slots for the vehicle's male connectors to slide into. Round connectors have circular holes for the same connection.

Go to a hardware store and select an adapter that joins the two different types of wiring harnesses.

Slide the 6-pin side of the adapter into the vehicle's harness by pushing the two together. Slide the 7-pin side of the adapter in the trailer's harness.

Test that the trailer's lights respond to the vehicle's systems as appropriate.

Items you will need

About the Author

Bob White began his writing career in 2006. Working in sales, he was a technical writer tasked with responding to requests for proposal. White has a Bachelor of Arts in computer science and a diploma in home inspection. He has also worked in construction, landscaping and the pool industry for more than 15 years.

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