In this post I show you How to Troubleshoot NNT Trailer Wiring Issues, find the problems, and repair them. In most cases the problem is really not wiring, but poor connections by the lights themselves.
But Wait…. Is this Homesteading?
While some may say that Troubleshooting NNT trailer wiring issues is not homesteading, I think that keeping your tools working properly is absolutely homesteading. If you can fix your tools yourself and keep them well maintained, it will save you a lot of money that you can use elsewhere on the homestead.
I hooked the trailer up the other day to go pick up a load of mulch. I check the lighting every time I hook my trailer up so I can save a little money by not getting a traffic ticket. When I checked the lights this time, the right side park lights were not working. I knew that I had to get to troubleshooting NNT trailer wiring issues.
Checking the Lights
The way I check the lights is to turn on the park lights and the hazard lights. If both the hazard and park lights work than that means that the brake lights will work as well. After you have the hazard and park lights on, simply walk around the trailer and make sure the lights work. You should have a yellow light that is steady on in the front of the trailer on each side and a red light facing out that is steady on in the back of the trailer on each side. As you walk to the rear of the trailer and are facing the front, you should see a light that is steady on in each lens as well as another light that is blinking brighter. If you don’t see this, you need to do some repairs.
Remove the Lens
The first step is to remove power to the trailer either by turning everything off in the vehicle that would make a light come on or by disconnecting the wiring harness. You do this so you don’t short stuff out and blow fuses.
The next step is to remove the red plastic lens by unscrewing and removing the four screws holding it on. The screws are small, so make sure you don’t drop them. I usually put the lens face down and put the screws in the lens until I need them again and then put the lens aside.
Remove the Light
Now you have access to the light and can remove it. Remove the light by twisting it counter clockwise and pushing in while you are twisting. It may take a little work of pushing and pulling while twisting to get it out.
Look into the Light
Now look at the light and make sure both filaments are there. While looking at the light from the top you should see two wires (filaments) going from side to side. They should not have a burned look to them. If they do or if one of the filaments is missing, you need a new light. Usually if a light is bad it is fairly obvious. In every case that I have had light issues it has not been the light itself that was the culprit.
There are two metal slats in the back of the light socket that the light bulb connects up against to get electric. Their job is to bend in and out when you push the light bulb in and out while supplying electric to the light. They sometimes bend in a little too much and do not make good contact with the light itself. If that is happening to you or if you think it is happening, you can remove the slats, straighten them out a little and put them back in place.
To remove the slats, you need to remove a small screw at the bottom of the slat that is holding it in. Once the screw is removed you can maneuver the slat out with a pair of needle nose pliers.
The first step is to clean any corrosion off of the slats where the light makes contact with the slat. Just simply scratch any corrosion off with a screwdriver. Then bend the slat so it is straight and put it back into the assembly. Once in place, put the screw in that holds the slat down.
Remember there are two slats, so repeat this process for the other slat.
Electric Post for your Slats
Another place that things can go wrong is connectivity to the metal post. There are wires coming in from the back as you are looking into the light fixture. The wires are connected to posts. You can actually jiggle the wires a little and see the posts move inside the assembly. You need to make sure that the slats are wedged firmly against the posts. If there is any corrosion, try to clean it up as best as you can so there is good contact.
Putting the Lights In
After you have cleaned all corrosion and straightened the slats you can put the light bulb back in. When looking at the light bulb, take note that it has two posts and the posts are at different levels on the light bulb. One post is closer to the electrical connection and one post is closer to the bulb. If you look into the socket, you’ll notice that the socket has a place for the post to sit and there are different levels in the socket itself. You will need to match these up in order to get the light in.
Once you know which post rests where in the socket, then you want to put the light into the socket. First you have to line the posts up with the groves in the socket so you can push the light in. Then you push the light into the socket and turn the light so the posts sit on the post holder in the socket.
Test the system
At this point I hook electric back up and test the system. Test the system the same way you did earlier in the section called ‘Checking the Lights’ above. If you still have issues, you need to make some more adjustments by following the above steps.
If you have repeated the steps and still don’t have working lights, you may need to get a multi-meter and test for opens or shorts in the wiring. That will be a subject for another post, maybe Troubleshooting NNT Trailer Wiring Issues Advanced.
If the lighting system now works, you can put the lens back on. Take the four screws and put them in you hand, put the lens on the trailer and use the four screws to secure the lens.
Check out our YouTube video below titled Troubleshooting NNT Trailer Wiring Issues.
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