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Last Updated on August 23, 2024 by Shera Mae Torollo
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Trailer Running Lights Not Working Troubleshooting Tips
If you’re experiencing issues with your trailer running lights not working, you’re not alone. Many face this common issue, which can be caused by various factors, from wiring problems to blown fuses. We will explore the step-by-step process to ensure optimum safety while on the road.
- Check the fuse: Start by inspecting the fuse controlling trailer lights.
- Inspect the wiring: Examine trailer light wiring for damage or issues.
- Test the light bulbs: Remove and inspect each trailer light bulb.
- Check the ground connection: Ensure a secure ground connection for trailer lights.
- Use a voltage tester: Test power flow to trailer lights with a tester.
Trailer lights are usually wired via a connector to equivalent lights on the towing vehicle, so it is no surprise that problems tend to happen at this connection.
That being said, there are several reasons why your trailer running lights are not working as they should. This article aims to highlight the necessary issues you could be facing and any solutions to those particular problems.
The four-terminal connector provides a tail, right brake and turn, ground return, and a left turn and brake signal.
Some larger connectors, particularly on larger travel trailers, come with electric brakes, 12V accessories port, and reverse lights.
The majority of wiring problems faced tend to begin right at the connectors. They could also be at the point that joins the light to the connection. Specific problem areas, such as the wiring flexes’ location, can be careless.
The following will show you how to recognize and fix your trailer lights. The good thing is that most of these fixes are easy and quick. Some tools will be required of you. They are:
- Continuity tester
- 4 1 screwdriver
- Jumper wire
- Tow vehicle tester
- Nut wire
- Electrical contact cleaner
- 220 grit sandpaper
- Wiring kit
- Replacement bulb
If your trailer has begun to show that it is aging, there is a high chance you have had issues with the running lights. Running lights must function properly, a prerequisite to safely operating the trailer.
It is for this reason that you have to check your lights frequently. Some issues, like lousy running light ground or a burnt bulb, can be pretty easy to solve.
Other problems can be pretty challenging to recognize and solve. Read on to discover the issues you might have and the particular fixes to those issues.
Troubleshooting the Trailer’s Running Lights Using a Tester
The first thing you should do is check your vehicle’s system. Ensure that your tow vehicle tester is inserted correctly in the car. Doing this lets you know if the trailer’s running lighting system is correctly functioning.
There are two kinds of wiring testers; you have to check the configuration of the vehicle’s plug. Take your time to hook up the trailer as you would typically do and connect the light harness of the trailer.
This will involve having someone else around as they would have to check to see if the trainer’s running lights, blinkers, and stoplights are correctly functioning.
If all of the lights are dim or not on, inspect the trailer’s light harness connection right at the truck.
Your first port of call would be to unplug the harness and then use a tester. The trailer light tester, when plugged in, would immediately inform you if the problem stems from your truck.
If there is a problem, you must check that all your truck’s lights function as they should.
Inspecting would help determine if your truck has a burnt-out light, blown fuse, or bad flasher. Ensure the connector is clean, and then check again. Additionally, you can check the connector for any faulty or damaged wiring.
If all the lights on the tester appear to function correctly, the problem likely lies in the trailer’s harness or lights. If so, we move on to the next troubleshooting step.
Clean the Connector Plugs
Before you begin, the socket and plug should be cleaned using a specialized cleaner. This is the step to take when you realize the lights aren’t on or appear dim.
The connector plugs should be cleaned using an electrical contact cleaner, and then a wire brush, preferably a fine one, should be used to clean the contacts.
Thoroughly Inspect the Trailer’s Ground Wiring
Take the time to inspect and clean the ground wire connections thoroughly. Once done, ensure the ground wire is securely fastened to the trailer.
Most running light issues tend to happen because of an issue with the ground wire.
Loosen the trailer’s ground screw so you can sand its wire terminal as well as the chassis contact using sandpaper. If, while inspecting and you notice the screw is rusted, you have to replace it.
Replace Any Bad Light Bulbs
If the steps above have not solved the problem causing your trailer’s running lights to malfunction, then there could be an issue with the bulbs. , your bulbs have gone wrong.
Remove the bulbs by slightly twisting them and ensure the ones you install work correctly before turning them reversely. If just a single light is out in your trailer, you might need to change only that bulb.
This can be done by removing the lens, replacing that bulb, and inspecting it to ensure it works correctly. If it does work as it should, then you are set.
Clean Any Corroded Sockets
Corrosion can be removed using sandpaper and a small dowel, enabling you to get into small spaces.
After doing the above steps, you still have trailer running lights that do not work; it could be that the socket and the contact points have been corroded.
To help you clean this, you will require some 220 grit sandpaper, a three-it-eight dowel, and hot glue. The sandpaper should be stuck to the dowel’s butt end using hot glue.
This will allow you to reach places that are usually inaccessible.
The contact points can be cleaned by spinning your dowel; simultaneously, you move it from one side to another. Once the contacts have been cleaned, apply some dielectric grease before inserting the bulb.
At this point, the bulb should be functioning correctly. However, if it still doesn’t work, you might want to inspect the mounting bolts to ensure adequate contact between them and the trailer’s frame.
When your inspection turns up corrosion, scrub it away using sandpaper. Recheck your lights.
Conduct a Continuity Test
The trailer’s wiring should be checked by conducting a continuity test. This is done by connecting the connector pins to a jumper wire and the sockets to a continuity tester. The continuity tester consists of a battery and a light bulb.
When the circuit is functioning correctly, the bulb lights up. Alligator clips can ensure the continuity connection is easy and quick.
If the running lights on a particular side still aren’t functioning, the wiring could break.
You can search for broken wiring by searching for the wire at the connector in the front and the back end that connects to the socket.
Using the alligator clips, a jumper cable should be connected to a connector pin, and the other end should be connected to your continuity tester.
If, after doing this, the light still doesn’t come on, then it is more than likely there is a break or bare spot. What you should do in this instance is to search for the break.
When locating locatereak, the wire should be cut at that end, and new connection solders should be ended. The insulation should be repaired using heat-shrinkable tubing.
The Last Plausible Solution would be to Replace the Entire Light System on the trailer.
You should not hesitate to change the trailer’s wiring if it is corrupted.
When no other solution works, and you keep discovering corroded parts, purchasing a wire harness for a reasonable price is possible. You get a new wire harness and a connector, lenses, and lights.
How do I know if my trailer fuse is Broken?
Determining if your trailer fuse is blown requires keenly observing a few signs. Firstly, malfunctioning or non-functioning lights are a standard indicator.
If your trailer lights are not working correctly, it might be due to a blown fuse. Furthermore, you can physically check the fuse.
A blown fuse typically has a broken or burned metal wire. You could also use a multimeter to check for continuity for an accurate diagnosis.
If the multimeter shows a lack of continuity, this signals that the circuit is broken and your trailer fuse is possibly blown.
Correct Trailer Maintenance
Proper maintenance of any equipment you have can help you not only extend the lifespan of your equipment but also reduce any unexpected costs. Here are a few steps you can take to ensure that your trailer is properly maintained.
Tire Inspection
Your tires have to be inspected, particularly if the trailer wobbles. Things such as uneven tread, cracking, and bulging should be checked.
You should only ever check and change your tire’s pressure when cold. Air should never be released or added when hot. Any damaged or worn tires should be replaced as soon as possible.
Cable Inspection
All the cables, as well as the cable attachments, should be inspected before you use the trailer.
Watch Where You Park
You must ensure that wherever you select to park and set up, your trailer is level and flat. If your trailer has a side awning or a slide-out, ensure that you have enough space for it.
If parked near a tree, watch out for any overhanging branches that could damage the trailer if they fall. Your wheels should be blocked before you open the trailer out.
Sanitize Your Water System
You must sanitize your freshwater system frequently. This helps to prevent bacteria growth and odors from forming. The water filter should be replaced at least once per year. You could also change it when the flow of water begins to slow.
To do this, you must first drain the tank with a bucket underneath. The fittings underneath and above the cartridge should be unscrewed. The filter should then be removed and a new one put in its place securely.
Dump Your Tanks
If you intend to store your trailer for a long time, it would be beneficial to dump your grey and black water tanks. If they are not the recommended two-thirds of the way complete, you can fill them with water and leave them.
Once empty, you should clean them, especially the black water tank, to ensure no solidification can hamper the tank’s effectiveness.
Summary
Facing an issue of trailer running lights not working can be troublesome, but few steps can be taken to identify the root cause and rectify the problem.
First and foremost, check the fuse that controls the trailer lights. A blown fuse could be a simple explanation for the lights not working.
If the fuse is in good condition, the next step is to inspect the wiring of the trailer light. Damaged or frayed wiring could be preventing the lights from functioning correctly.
Additionally, consider testing each light bulb individually, as a faulty bulb can often be the cause behind Trailer Running Lights.
It is not Working. Remove each bulb and inspect for any damage or blown filaments. Moreover, ensure a secure ground connection for the trailer lights. A poor ground connection can lead to inconsistent or non-working lights.
Lastly, utilize a voltage tester to check if power is supplied to the trailer lights appropriately. This will confirm if the issue lies in the power supply or elsewhere.
To ensure proper function, it’s essential to thoroughly inspect the fuse, wiring, light bulbs, and ground connection to test voltage.
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