7 Pin Trailer Running Lights Not Working [Troubleshooting Guide]

You turn on the running lights, and suddenly it’s not working. All the switches are connected, and everything is fine, but it’s still not working. 

Then you’re wondering, what could go wrong? Why are the 7 pin trailer running lights not working? Is there anything wrong with there?

Yes, there could be. In a 7-pin plug, the brown pin is usually connected to the running lights. Maybe you didn’t properly get it cleaned for a long time, the connectors and plugs got loose, and the wiring problem and a blown fuse can also be the reason.

Whatever the reason might be, don’t worry! We got your back. We provided all the specific yet detailed information on what could go wrong. Besides, we also provided to solve the problems.

Let’s get to know one by one. But first, just a brief idea about all the types of pins in an RV and the trailer wirings.

Types of Pin In an RV and Trailer Wiring: Basics

Types of Pin In an RV and Trailer Wiring
Source: etrailer

Here, we will discuss the basics of a camper’s wiring, specifically the pin. There are a few types of pins you will find in a trailer. Those are;

  • 4-pin.
  • 5-pin.
  • 6-pin.
  • 7-pin (Round).
  • 7-pin (RV Blade – SAE).
  • 7-pin (RV Blade – Traditional).

So, to be specific, there are six types of pins in a camper. Let’s get an overview.

4-pin: In a 4-pin wiring diagram, there are four colors, green, yellow, brown, and white. Green and yellow work as a right and left turn, respectively, and both work as brakes. Brown works for the taillights and white works for the ground.

5-pin: Everything in 5-pin works similarly to 4-pin. Green (right turn + break), yellow (left turn + break), brown (taillights), white (ground), and the 5th color is blue, which works as a reverse light.

6-pin: As with the rest, the green, yellow, white, and brown work similarly. But, the 5th and 6th colors are blue and black, which work for the electric brake and 12-V.

7-pin (Round): In the 7-pin wiring round system, the green (right turn + break), yellow (left turn + break), brown (taillights), and white (ground) work similarly to the rest of them. But, the black, blue, and red represent the reverse lights, electric brake, and auxiliary power, respectively.

7-pin (RV Blade – SAE): There are a few differences with the round 7-pin wiring system. The green, yellow, brown, and white work as the rest of the wiring system. But, electric brake, reverse light, and 12-V are represented by blue, grey, and orange color.

7-pin (RV Blade – Traditional): Same as the 7-pin (RV Blade – SAE).

As we can see, there are similarities in work patterns among all the pin systems or wiring. Besides, you will find the following;

  • 4-pin wiring in flat and round.
  • 5-pin in flat.
  • 6-pin in square and round.
  • And 7-pin in the round, traditional, and SAE configurations.

Now that we have a basic understanding of how the entire wiring system is connected, we can move into the next section. In our case, we’re dealing with a 7-pin wiring system in the camper.

Let’s go through all the possible reasons why running lights are not working and the solutions for those issues.

7 Pin Trailer Running Lights Not Working [Reasons and Fixes]

7 Pin Trailer Running Lights Not Working

The 7-pin wiring system is the most complex among all of them. Many things can go wrong when dealing with a 7-pin, not to mention all three different types.

Many things can go wrong in a wiring system, such as brass connectors, auxiliary circuits, the ground pin, plug, etc. 

Whatever the problem might be, they all have solutions for it. Let’s see them one by one.

Maintenance Problem

If you’re not cleaning the plug from time to time, that might cause the problem. As we discussed, some pins connect everything throughout the wiring system.

Besides, all the lights’ power supply is controlled by the plug. Sometimes, the pins of the plug can get loose. The simple solution is to tighten it.

And, of course, clean the plug area properly. And ensure that you are cleaning the plugs regularly.

One important thing to note is the socket; you must connect the cord firmly. Otherwise, it won’t work.

Brass Connectors Problem

Most of the time, the problem lies in the brass connectors. Brass connectors can go faulty or bend due to many reasons. Maybe something related to the terminal has gone wrong and needs fixing. 

In that case, you need to check the terminals one by one. Besides, it won’t be a problem if the brass connectors are already connected.

But, if all the connectors are connected, and even the running lights are working, you might need to replace the entire box. It’s not a great idea to replace the wires connected to the brass connectors, but you can do that.

In the case of bend connectors connection, you can just bend it back. But that’s just temporary. It would be the optimum solution to get a new plug and replace it with the old one. If you cannot figure out and fix the solution, you might need a professional’s help.

Wiring Problem

The main reason could be lying in the ground wire. Sometimes you might find corrosion which ultimately marred the connection between the pin and the lights. Thus, it results in the lights not working.

Or sometimes, the wiring system went terribly due to heavy use or for using for a long time. If possible, try to tighten the connection between the wire and the pin.

But, sometimes, the wire is not in the state to repair. In this situation, the only solution is to replace the wiring with new ones.

Blown Fuse

Every camper comes with different types of electric systems. And all the components that go with it are essential. Fuse is one of them that can be a reason as well.

There is a fuse specifically for the running lights in your camper. Due to irregular use or power supply, overheating can blow a fuse. That resulted in the cutting of the power supply.

All you can do is buy a fuse from your nearest store and replace it. That might solve the issue.

Final Words

The 7-pin plug can be a small part of the entire power supply system but an essential one. There can be many problems regarding this, one of them is lights, specifically running lights.

We discussed all the possible problems and the reasons behind them. And we tried to provide all the information so that you can understand the situation and decide how to solve your running lights problem. 

We hope this article helped! Good luck!

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