7-Way Trailer & RV Plug Diagram

This guide is here to help you. If you can not figure out your wiring even after reading this guide, then contact your LOCAL mechanic or trailer shop for help. We suggest this because it is difficult to diagnose your wiring issue over the phone.  If you are local to us, give us a call if you want to schedule a time to have your trailer fixed.
7 Way RV Style Trailer Plug Diagram - Truck Side 7 Way RV Style Trailer Plug Diagram - Trailer Side


It’s the dreaded 7-Way Trailer & RV plug that we all have come to know and love. Most new vehicles equipped with a tow package have connectors. Trailers with electric brakes need them too. The 7-Way Trailer Plug is around 2″ diameter connector that allows an additional pin for an auxiliary 12-volt power or backup lights. It is usually used for towing a heavy-duty landscaping trailer, car trailer, boat trailer, horse trailer, travel trailer, construction trailer, and larger trailers.

Here at AJ’s, we are all too familiar with the accidents people have with the plugs; forgetting to unplug and pulling away, dragging it on the ground. With all the abuse and day-to-day wear and tear, you may find yourself repairing or replacing one sooner or later.

If you’ve ever looked at a 7-Way RV Trailer Connector, you have probably stood there scratching your head in confusion. We are going to do our best to simplify that, mainly with a good, color coded diagram. Download this guide, print it and keep it in your toolbox for future reference.

When referencing the 7-Way RV Plug diagram, make sure you are looking at the plug the way the diagram is showing you. Having the wires backward will cause problems. Keep in mind that it isn’t always as simple as matching the colors like you might be inclined to do. Match the functions, not the colors. Make sure your ground wire, which is typically white, is securely attached to the frame on both the truck and trailer side. The ground wire should be large enough to handle the entire load, do not depend on grounding through the ball.

Grease your trailer plug. A thin coat of grease will help prevent copper oxide from building up. That is the green stuff that forms when oxygen from the air or water come in contact with copper. You may think the rubber caps protect the plug but they tend to hold the water in.

If your brake lights work, or your marker lights work, but nothing works when you turn on both at the same time, your trailer is not grounded to the truck. So, if you step on the brakes and all the trailer lights go out, then you need to ground your trailer to your truck with the ground wire.

7-Way RV Trailer Plug Guide
(Print this guide and save for future reference.)

How to Wire 7 Plug
(Print the video notes for future reference.)

Best of luck, and happy towing to you!