Having trouble with your RV lights not working when plugged into shore power? Don’t worry, you’re not alone. Many RV owners run into this issue at some point, and it can be a confusing problem to solve. Luckily, the solution is usually simple and typically involves checking the battery, converter, or fuse. This article will discuss the various components of your RV’s electrical system and how they might be related to your RV lights not working on shore power.
Below is your guide on how to figure out your lighting system problem. I always like to start with the simplest solution and work my way up to more complex tests. Simple things often resolve the issues, and it’s best to try those out before digging too deep and wasting time.
Table of Contents
- Shore Power
- Battery DC Power
- RV Converter
- How to Test Battery and Converter
- Battery Disconnect Switch
- Fuse
- Light Switch
- Final Thoughts
Shore Power
When we say shore power, we are talking about being plugged into a house or campsite power source. This connection allows many electrical items to work in your RV, including outlets and an air conditioner. The power brought in is usually 120v ac and can service all of your electrical needs.
Even when using a generator, this is considered RV shore power as the power supply is still 120v ac with your RV does not know the difference between the two.
Battery DC Power
First, let’s review what power your RV lights use. What’s interesting is that your RV lights operate on your 12V DC battery, which is different than 120V AC power. So even though you are plugged into the campsite with shore power, you still need to go through your converter and battery to get the correct 12V DC voltage for your lights.
So if you are connected to shore power and the lights are not working, the issue is likely associated with your battery or the system that converts the electric power into battery power.
RV Converter
We just reviewed that shore power at 120v is converted to battery power of 12v. So how does your RV do that? The answer is by the use of a converter. This device takes 120-volt house power from a campground or your generator and turns it into 12-volt battery power for your RV appliances and lights.
The converter also acts as a battery charger when plugged into house power. So if there is an issue with your converter, this will cause a weak battery and will not allow your lights or other 12v systems in your camper to work.
Just a note, you also have a battery inverter in your RV. This is different from a converter because an inverter takes 12-volt direct current (DC) power from the RV’s batteries and converts it into alternating current (AC), which can then be used to run appliances and other electrical devices.
How to Test Battery and Converter
How do you check if your battery and converter are working? The tried-and-true method is to get a multimeter and test the wires going to lights or other appliances that run on 12v. If you get at least 12V of the battery voltage, your battery and converter are good.
If you don’t have a multimeter and want to do a quick test, that’s easy. Find another appliance that runs on battery voltage. Usually your RV water pump runs on a 12v battery. If that pump is still running strong and you don’t sense any weakness, your battery and converter are likely ok.
If you are thinking about trying to use an outlet to test your battery, that doesn’t work as well. Why? Because your RV outlets run appliances that are 120V. So plugging in a hair dryer to the outlet to see if the battery is functioning will not work. The outlets get the power directly from your shore power and are not associated with your interior lights.
Also, testing 120v appliances, such as the air conditioner, won’t work either. An air conditioner draws a lot of power and does not use the battery for any function.
Now, if you don’t have power to any other 12V appliance, the issue is likely your battery or converter.
Battery Disconnect Switch
One issue that can be associated with a battery issue is a battery disconnect problem. If you have a faulty battery disconnect switch, or if left in the off position, this will cut the battery power to your RV and will not allow things such as lights to work.
A disconnect switch is usually mounted near the batteries in the front or rear of an RV. It allows you to easily turn off all electrical loads from the battery when it’s not in use by flipping a switch or pushing a button. This prevents any drains on the batteries that could cause them to discharge unexpectedly and damage other parts of your RV. It also helps preserve their lifespan and keeps them running smoothly during storage or travel.
Check my post on RV battery disconnect problems if you are not getting battery power to your RV.
Once you confirm the battery disconnect switch and converter test, let’s move on to the next possible culprit, which is the fuse.
Fuse
An RV fuse is a type of safety device that protects the wiring and circuits in your RV by breaking the circuit when too much current flows through it. The fuse contains a wire or strip of metal that melts when too much current passes through it, interrupting the flow and preventing further damage. It’s important to choose the right size of RV fuse for your vehicle, as using one with too low an amperage rating could cause more harm than good.
Fuses work on 12V DC (battery), while breakers work on 120V (shore power). So when you have an electrical issue, the fuse can easily play a part in the problem on the 12V side.
How to check Fuse
Maybe you have a blown fuse, and the simple fix is just to replace it. The next step will be to go to your circuit breaker and check your fuses. Don’t worry, you will see a lot of fuses and breakers, which may be overwhelming. The nice thing is that your circuit breaker is labeled. Find the fuse that is labeled the interior lights. Pull the fuse and visually inspect if the wire blade is intact or broken. If broken, replace the fuse with the same amp fuse. Hopefully, you have a few fuses lying around. If not, go to any home or auto center to pick it up.
Also, check the breaker, if it has tripped. If the breaker has tripped, reset it by moving back to the on position. Breakers usually snap into place, so you should feel it go into position confidently.
If both your fuses and breakers seem to have been okay, the light switch is the last item to check.
Light Switch
If you have run through all the tests above and have not discovered the issue, then the next step would be to check the light switch itself. Depending on the set-up of your interior lights in your RV, you may have one or multiple switches.
If you have some switches that work and some don’t, the issue should be isolated to the defective switch. If none of your lights work with multiple switches, the problem is likely to be your 12V system as a whole or some wiring that leads to the function of your lights.
Final Thoughts
Lights not working on shore power can be frustrating. With the guide above, you can hopefully pinpoint and resolve the issue. The likely culprit is the 12v system that supplies your interior lights. This system comprises your battery, converter, and fuses, which we outlined how to test. If none of the fixes work, I suggest you connect with an RV technician, as the issue could be more in-depth with wiring or contactors associated with your 12v system.
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.