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Trailer Lights Not Working On One Side: How to Fix?

Trailer Lights Not Working On One Side: How to Fix?

Are you having trouble with your trailer lights? Do they work on one side but not the other? This can be frustrating and dangerous while towing your trailer. There can be several reasons why your trailer lights are not working on one side, but the good news is that there are some simple fixes that you can explore before calling for professional help. In this blog post, we will go over the common causes of trailer light malfunctions, how you can troubleshoot the issue, and how to fix trailer lights that are not working on one side.

Trailer Lights: All You Need to Know

One of the most crucial parts of owning a trailer is ensuring that its lights are working correctly. Trailer lights are used to signal turns, brake lights, and signal to the rest of people on the road about your presence. It is crucial to understand everything about trailer lights, including proper installation, maintenance, and understanding the warning signs of wear and tear. There is all the information you have to know about trailer lights, from the different types available to their significance on the road.

First of all, it is important to note that trailer lights can be categorized into four main types: brake lights, tail lights, turn signal lights, and hazard lights. Tail lights are typically red and they show the back edges of your trailer. Brake lights are activated when the brakes are applied, signaling drivers behind you that you are stopping. Turn signal lights are amber and inform the driver behind you when you are making a turn. Lastly, hazard lights are used when the vehicle is parked on the side of the road or in an emergency situation.

It is crucial to install the trailer lights correctly. Faulty wiring and faulty trailer lights are major safety hazards when towing a trailer. Before you set off, it is critical to check the wiring, light connections, and all other components of the light system in your trailer. Proper maintenance is also essential to ensure that your lights are working correctly. This includes cleaning the lights regularly, replacing faulty bulbs and wiring, and checking the battery. A simple visual inspection before each journey can help prevent road mishaps.

It is essential to understand the warning signs of a malfunctioning trailer light. If you notice that the trailer lights are working incorrectly, then it is time to fix the problem. Warning signs include flickering lights, dimming lights, or burnt-out bulbs. Continuously monitoring your trailer lights ensures that you prevent the risk of getting pulled over by law enforcement.

When selecting a trailer light, it is crucial to look for high-quality lights that are durable and weather-resistant. LED lights are the preferred choice because they last longer and use less energy than traditional lights. The wiring and connection system should also be easy to install and test before hitting the road. It is advisable to be cautious of cheap trailer lights that may compromise the safety of you or other road users.

Trailer lights are essential in ensuring road safety when towing a trailer. Knowing the basics of trailer lights can help you handle trailer light issues and ensure your trailer remains visible to other road users. Proper installation, regular maintenance, understanding warning signs, and selecting the right trailer lights should be a top priority. Next time you take a journey with your trailer, ensure that your trailer lights are working correctly and be ready to hit the road with confidence.

Trailer Lights

The Most Common Reasons Why the Lights Not Working On One Side

If you’re going for a road trip or transportation and your trailer lights are not working on one side, that can be troublesome. It is a situation that is not only frustrating but also dangerous if you’re driving on highways in the dark. There are various reasons why trailer lights may not be working on one side. Let’s go over the most common reasons for this issue, so you can diagnose the problem and fix it before hitting the road.

Faulty Bulbs:

The most common cause of trailer lights not working on one side is faulty or burnout bulbs. Trailer bulbs can get damaged by vibrations during transit and may require replacement. You can test this by replacing the bulb with a new one and checking if the light works or not. If the light still does not work, then there could be another reason for the problem. [1]

Corroded Connections:

Another reason for trailer lights not working on one side is corroded connections. If the connections are corroded or dirty, then they can prevent power from reaching the bulbs. Corrosion can be caused by moisture and water seeping into the connections. To fix this issue, try cleaning the connectors with a wire brush or a plug cleaner. [2]

Wiring Issues:

Wiring issues can also be the culprit behind trailer lights not working on one side. If the wiring on one side of the trailer is damaged or disconnected, then the lights will not work. Check the wiring harness for any damage or broken connections. You can also inspect the wires for burnouts or cuts. If there are any issues, you may need to replace the wiring harness. [2]

Bad grounds:

Grounding is an essential part of the electrical system in a trailer. If there is a bad ground connection for the trailer lights, then they may not work on one side. Check the ground wire connection for any damage or loose connections. Make sure that the grounding point is clean and free from any rust or corrosion.

A blown fuse:

If everything else seems fine, then the problem may be a blown fuse. The fuse box is typically located under the dashboard or in the engine bay. Refer to your owner’s manual to locate the fuse box and determine which fuse corresponds with the trailer lights. Once located, check the fuse for any damage or burnt marks. Replace the fuse with a new one if it is blown.

Trailer lights not working on one side can be a significant safety hazard. There are various reasons why this issue can occur, including faulty bulbs, corroded connections, wiring issues, bad grounds, and blown fuses. By identifying the problem, you can take appropriate steps to either fix it or replace the necessary parts. Before embarking on any trip, ensure to test trailer lights on both sides by taking a short drive or using a multi-tester. Remember, safety first should be the top priority when using a trailer.

A blown fuse

How to Fix: a Step-By-Step Guide

When out on the open road, it’s important to have functioning lights on your RV. But what happens when they suddenly stop working on one side? This can be frustrating and dangerous, but fortunately, with a little troubleshooting, you can often get the problem fixed yourself. Here we’ll guide you through the steps of fixing RV lights not working on one side. We’ll cover everything from checking bulbs to ground wire connections so you can get back on the road safely.

Step 1: Check the Bulbs

The first step in fixing RV lights not working on one side is to check the bulbs. Sometimes, a burnt-out bulb is the only problem. Inspect all bulbs on the non-functioning side for damage or darkening. If the bulb is dark, it’s time for a replacement. It’s also a good idea to swap out all bulbs regardless of how they look, as they can still fail even if they appear to function.

Step 2: Check the Wiring

If the bulbs are all okay, the next step is to inspect the wiring. Check for any frayed or damaged wires that could be interrupting power to the light. You may need to remove any covers protecting the wires, so be sure to have the necessary tools on hand. If you find any damage, cut out the bad piece of wire and splice in a new one. Make sure to test the light again post-splice.

Step 3: Check the Fuses

If the wiring appears to be in good shape, the issue could stem from a blown fuse. Check your RV owner’s manual for the location of your RV’s fuse box. Look for any blown fuses, and if you find any, replace them accordingly. You may have to try a few fuses before finding the right one, but once replaced, your RV’s lights should function again.

Step 4: Check the Ground Wire

Another possible culprit for RV lights not working on one side is the ground wire. Check your RV manual to find its location. Corrosion can form on the wire’s connector or where it connects to metal. If it appears likely that corrosion is the problem, unplug the ground wire, clean the connection, and plug it back in. Test the light again to ensure it’s functioning.

Check the Ground Wire

Step 5: Check With a Professional

If you’ve gone through these steps without any success in finding the cause of the issue, it’s time to bring in the pros. Sometimes an electrical issue needs the help of an expert. An experienced RV electrician can pinpoint any underlying issues you may have missed and give you peace of mind that your RV is safe to get back on the road.

We hope this guide on how to fix RV lights not working on one side has been helpful in getting your RV’s lighting back up and running. Always start with the simple stuff: bulbs and connections. Next, check your wiring and fuses, and finally, clean and check your ground wire. If these discernable fixes don’t work, then it’s time for professional assistance. With a little patience and thoroughness, you can get your RV ready for your next adventure in no time. Happy travels!

When to Seek Professional Help

The charm of RV trips is often associated with the sense of freedom they offer. However, problems with the RV can cause unwarranted frustrations and inconveniences. One of the common issues you may encounter in your RV journey is when the RV lights are not working on one side. The cause of the problem can vary from a simple blown fuse to complex wiring issues. So let’s check when it is time to seek professional help.

The RV wiring system is relatively complex compared to your average house wiring since it incorporates distinct 12-volt and 110-volt circuits. The 12-volt circuits are responsible for running essential RV systems such as lighting, refrigeration, and water pump. The 110-volt system takes care of powering the RV’s AC outlets and appliances when plugged into a power source. Now that we understand the dual wiring systems let’s see when it is better to seek professional help.

If you have exhausted the above-mentioned methods and your one-side RV light still isn’t working, it is time to seek professional help. RV electrical systems are complex, and it may be challenging to identify and fix more severe electrical issues. A professional technician will have the necessary tools, knowledge, and experience to repair your RV lights.

RV lights not working on one side is a common issue that can appear at any time on your journey. The problem can be due to something as simple as a blown fuse or as complex as electrical wiring issues. By understanding the RV’s wiring system and knowing when to seek professional help, you can troubleshoot and rectify most problems. It is essential to have a basic understanding of the issue so you can determine whether it is a quick fix or a severe electrical problem that requires immediate attention. By adhering to these guidelines, your RV travel will be stress-free and enjoyable.

When to Seek Professional Help


Why is only one side of my trailer lights working?

If you’re noticing that only one side of your trailer lights is functioning correctly, it’s likely due to a wiring issue. When hauling a trailer, the electrical connections between the towing and trailer vehicles are crucial. Any loose or damaged wiring can result in one side of your trailer lights being unresponsive. To diagnose the problem: start by checking that all light bulbs are properly installed and functioning on the non-working side. If the bulbs are fine, the next step is to determine if the issue is with the wiring. Use a multimeter to test the electrical connections for continuity, checking for any breaks or damage in the wiring.

Why is there no power to one side of my trailer lights?

If you’re not getting any power to one side of your trailer lights, the most common culprit is a blown fuse. Pull out the fuse box for your towing vehicle and examine the fuses related to the trailer lights. If one is blown, replace it and test the lights again. If this doesn’t fix the problem, it’s possible that the wiring on the non-working side is damaged.

Why does one trailer light work but not the other?

In this scenario, it’s likely that the non-working light has a loose or corroded wire connection. Start by checking the bulbs on both sides of the trailer lights. If both are intact, continue examining the wiring connections. To pinpoint the issue, use a circuit tester to determine where the lack of power is located.

Why does one trailer light work

Why is the turn signal not working on one side of my trailer?

If you’re not getting a turn signal on only one side of the trailer, it’s usually due to faulty wiring or a bad connection. Start by checking the turn signal bulbs to see if they’re functioning properly. Then, examine the wiring connections and check for any signs of damage or corrosion. It’s possible that a connection needs cleaning or tightening to restore power to the turn signal.

Useful Video: Trailer Lights Not Working – Wiring Issue – Problem Solved!


In conclusion, trailer light malfunctions can be easily resolved if you know what to look for. When your trailer lights are not working on one side, the most likely causes are faulty wiring and poor bulb or connection. Troubleshooting the issue requires identification of the problem’s root cause and utilizing the proper repair method such as checking the connections, inspecting the bulbs, examining the wiring, and checking ground connectivity. Always start by checking the bulbs and fuses, then moving on to testing the electrical connections and wires. Regular maintenance and proper storage can also go a long way in preventing trailer light issues. So, the next time you’re in a bind, don’t hesitate to dive into some basic troubleshooting! By following these simple tips, you will be able to fix your trailer lights in no time. However, if you are not confident in your mechanical repair skills, it’s best to seek professional help to avoid further damage. Happy towing!

  1. https://statestreetautorepair.com/blog/common-reasons-your-headlights-stop-working#:~:text=One%20headlight%20doesn’t%20work,a%20wiring%20or%20fuse%20problem.
  2. https://teambmpro.com/12v-guru-fixing-faulty-lights/#:~:text=The%20most%20common%20of%20reasons,ground%20for%20the%2012V%20circuitry.