Changing a Fuse in Christmas Lights: What Do You Need and How to Do It

The holiday season is upon us and no matter which one you celebrate, you might always have a reason to hang Christmas lights in and around your house. If you’re like most of us, chances are that you already have an existing set of Christmas Lights that you previously used in last year’s holiday season.

You might be spending hours hanging Christmas Lights in the interior and exterior premises of your house only to find that they don’t light up when you plug them in. And more often than not, it’s these lights’ fuses that stop functioning to render your light useless.

In this post, we’ll be helping you figure out how to locate the fuses in your Christmas lights, how you can take them out, and replace them with new ones when the time comes.

Make sure your fuse is blown out

The biggest guilty party when it comes to malfunctioning Christmas lights are blown fuses. If your entire strip of Christmas lights is no longer working, then there’s a high likelihood that its fuse has burnt out. These holiday lights come with cartridge fuses that are placed right inside the cord plug and can thus be taken out easily.

These fuses, even though tiny, will have metal-plated ends on both sides and a metal filament inside a glass chamber. When the fuse is blown out, it will appear dark in color and will no longer work. Some fuses will not appear to be blown out, but it will still be burnt and not usable. You can examine these fuses by checking whether there’s a break in the metal filament inside the fuse.

You can check whether the fuse is blown out in the step-by-step guide we’ve prepared for fixing fuses in Christmas Lights below.

Do you have everything you need to change the fuse?

In order to replace an existing fuse in Christmas Lights and replace it with a new one, you will need the following tools:

Screwdriver (small flathead, mostly)
Replacement Fuses
Lightkeeper Pro or LED Keeper (for testing fuse)

How to replace a fuse in Christmas Lights

To start replacing the fuse in your Christmas lights, you can follow the steps mentioned below carefully.

Locate the fuse panel on your Christmas lights

The fuse panels on most holiday lights are placed inside the plug cover and can be easily accessed by prying it open. It’s important that you unplug the lights from the power point and then proceed to do find the plug. Make sure you pull the plug off the wall by firmly holding the socket and not by pulling the wires.

If you have multiple Christmas lights, you will need to line up plug covers of all of them and then proceed to open the fuse panel.

Open the fuse panel

Some holiday lights let you access the fuse panel directly by sliding the door that covers the fuse. On one side of the plug cover, the sliding door will be indicated using an arrow that points away from the cord.

Some plug covers will have screws that tighten the sliding door and can only be opened after unscrewing them using a screwdriver. You can open the fuse panel by sliding the concealing door using your fingernails on the grooves of the socket door.

If the door is tightly shut, use a screwdriver or a utility knife to fit it inside the gap, and push this door up to open the panel. When using the screwdriver or utility knife, make sure you don’t exert too much pressure, or else the socket, fuses, or fuse panel might get damaged in the process.

Remove the fuses from Christmas lights

Some lights have two fuses while others will only include one; so make sure the fuse panel doors are completely open to reveal all of them.

When the fuse panel is open, turn the plug cover upside down so that the fuses fall onto your hand. If not, use a small flat-head screwdriver to pull the fuses out of their panel.

When you pry the fuses off of their slot, make sure you don’t lose them as they’re really small in size.

Inspect the removed fuses (Optional)

In most cases, burnt fuses can be easily recognized as they’ll have an obviously burnt shade on the outside. However, some burnt fuses won’t be obvious to the naked eye and you might need a voltmeter or a Fuse Tester. You will find an included Fuse Tester if you own either the LightKeeper Pro or an LED Keeper.

To check for a blown fuse using the LightKeeper Pro or an LED Keeper, simply place the fuse inside the Fuse Tester slot that’s located at the top of both these devices. Place the fuse in such a way that the fuse touches the metal contacts on both ends.

If the fuse is properly working, a red LED will light up at the top of the device. If no light appears here, then it means that your fuse is blown and can no longer be used with the lights.

In case you don’t own a tool that has a fuse tester inbuilt, then you can check for a not-so-obvious blown fuse by looking at it under the bright sky or against any light source. When looking at the fuse, if you see an unbroken piece of wire running between the two metal ends, then it means that the fuse is working.

This step lets you find out which fuses to replace and which ones to not since some plugs will have two fuses and might not need to take both of them out.

Insert new fuses back into the panel

Once you have found which fuse is malfunctioning, you can replace them with another identical fuse of the same size and rating. You can usually check the fuse rating of replacement fuses by looking at the inscriptions on the plug.

Some high-quality Christmas lights come with a pack of extra bulbs and fuses which you can easily replace at a later time. But if you haven’t stored them or weren’t provided one, you can head over to your nearest home improvement/electronics/discount store. These spare fuses can be seen in little plastic pouches next to Christmas light sets.

You can also check the new fuses with the Fuse Tester tool inside the LightKeeper Pro or LED Keeper to make sure you’re only replacing the old ones with working alternatives.

Once you have the spare fuses, you can replace the non-functioning fuses in the light plug with these. To do that, place these replacement fuses on to the fuse panel after you have opened the fuse door. You can pop them in place in a similar fashion as you would place a battery onto a remote control.

Make sure the fuses sit tightly in place and then shut the door of the fuse panel by sliding it. If the door is stuck, use a flat head screwdriver or a knife to push the ridges of the door to shut the fuse panel close.

After you have replaced the fuses and properly closed them, plug the lights back in and test your Christmas lights to see if they work now.

If that doesn’t work, check where the problem is

Once you have replaced the fuses but your Christmas lights still don’t illuminate, then it means there’s a problem other than just burnt fuses. You can check where your problem is originating from and fix them by: