If your RV lights are not working and your fuse is good, this post will help guide you to the solution. Knowing that your fuse is good, you can start to focus on other potential causes. Many common causes of lights not working are a bad bulb, loose wiring, or bad ground. In this post, we will review the fixes for this issue, including:
- Checking Power
- How to check a bulb
- Wiring
- Switch
We will go through the steps for checking your RV light that is not working. And the below process will work for most RV lights, including interior lights, running lights or even tail lights. These lights have the same power source (12-volt battery) and will have a positive and negative cable. We will run through the common locations and solutions to lights not working.
Table of Contents
Fuse Panel
Let’s first take a look at the fuse panel. As you can see, the panel is full of breakers and fuses. Generally, a circuit breaker is ac power, and a fuse is dc power from the battery. All your lights are powered by the 12 V battery and will have a fuse for each set of wires.
Your panel will have a series of fuses, one on top of another. And you will notice that the panel is labeled for each location of the fuse.
There have been instances where I heard that a panel was mislabeled at the factory. You will notice that the panel is usually written, and mistakes can happen. Either the panel was incorrectly marked, or the RV builders misconnected a group of wires to a different fuse location.
As a double-check, check the surrounding fuses to ensure that the real fuse controlling the lights is the one you are looking at.
Also, another good practice is to make sure the fuses are securely pressed into the panel box. Any loose connection of the fuse or if it is not properly seated in the panel will cause things like lights not to work.
Checking Power
Knowing that your fuse is good is a clue for looking at other possible issues that could be causing your lights not to work. With a blown fuse, you would have an electrical interruption as the wire would be disconnected from the power source.
Even if connected to shore power, your lights need RV batteries for the 12 volts to operate properly.
To further test the extent of the problem, do a quick test on other battery-powered appliances in your RV. Besides interior lights, your water pump, brake lights, turn signal, and running lights, are also powered by your battery. For more info on everything powered by your battery, visit my post on what runs off the battery in a travel trailer.
No need to check things like your outlet, as this is ac power you get from shore power and not your battery. All your RV lights come from your battery power, so that will be the focus.
If any other battery appliances still work, then you are getting battery power, and you should move forward to isolate the issue.
Bulb
I always like to start off with the simplest solution before diving into the more challenging fixes.
First, check your bulbs to ensure they are working and the filament or LED diode in not damaged.
A brake light and signal light have a double filament. If one of the filaments is damaged, you may not get your lights working. To do a quick check, look at the bulb and see if there is any visual damage. It’s tough to see that filament wire, so you may have to look close.
If the bulb looks good and you want to make sure, here is a quick and easy way to know. Switch the bulb with another bulb in your RV. If that light bulb is still out in the new location, then you know it was indeed just the light bulb. If the bulb worked in the new location, then the light bulb is still good and not the problem.
Wiring
The next possible issue is the wiring. This could start anywhere from your battery to the light bulb itself.
Start by visually inspecting the wire that leads from your bulb to the battery. Inspect for any damage or corrosion along the wire or at any of the connections. With wiring, any corrosion or damage to a wire can cause a short and cause the lights not to work.
Another culprit in wiring issues is the ground wire. Since lights need both positive and negative power to operate, any issue in the negative (ground) wire will cause the lights not to work. For more information, visit my post on how to check a trailer for a bad ground wire.
Switch
If your issue is a light fixture or multiple interior lights, the likely cause could be the light switch itself. An RV switch is very similar to that a home switch. You may have just one or two switches operating many lights. If that switch is bad, then any light on the switch will not work.
A light switch is your positive wire, with a switch acting as a disconnect to that wire. When you turn on your light, the positive cable connects, and the power flows to the light. When you turn off your light, that switch disconnects the wire, stopping the power flow and not turning on the lights.
To check your light switch, unscrew it from the wall. Check the wire connections to see if there is a loose connection from the wire to the switch. If all looks good there, let’s check the switch itself.
Get a multimeter and set it to continuity. Place the meter probes on each end of the light switch. If you hear the beeping turn on and off as you turn the switch on and off, your switch is good. If there is no beeping or continuity as you turn the switch on and off, the switch is bad and needs to be replaced.
Final Thoughts
When your RV lights are not working, but your fuse is good, the issue could be loose wiring, a switch, or the bulb itself. First, check the bulb and make sure the filament or LED diodes are not broken or damaged. Then check for any loose wiring from the battery to the fuse box. Then finally, check to see if the switch is bad.
Tony is an avid camper and RV traveler. He fell in love with camping on his first RV trip with his wife over 25 years ago. Tony loves sharing lessons learned and tips about RV maintenance and safe traveling.
