How to fix Christmas lights—what to do with a blown fuse, a disconnected wire, or a broken lightbulb

Wondering how to fix Christmas lights? Whether you've already put your decorations up, or are planning to in the next few weeks, dealing with broken festive lights is a common issue at this time of year—especially if you reuse yours year after year. But below, we've shared how to quickly fix some of the most common lighting problems, so your home will be aglow before you know it.

When it comes to the most popular Christmas tree decorating ideas, warm white lights or colorful LED lights are some of the most popular options—a tree isn't a tree during the holidays without them.

But whether you have one of the best artificial Christmas trees, or a real one, it's often all too common to find when pulling them out of storage that, as soon as you are ready to decorate, either a fuse has blown, one or two of the bulbs has cracked or broken, or the wires have been (seemingly) irreparably tangled. Learn how to fix Christmas lights yourself with our guide below—be they hanging outside, on your tree, or on your mantel—so that your home can look as impressive as possible this festive season. 

How to fix Christmas lights—four causes and how to solve them

1. Disconnected/loose light bulbs

Fairy lights are one of the most important pieces when planning your Christmas decorating ideas. But disconnect lights are guaranteed to put a dampener on things. If yours appear to be disconnected, the first thing to look out for is any loose light bulbs on your string of Christmas lights. If they are, solving the problem could be as simple as the light not being pushed into the power source properly.

Thomas Goodman, a construction and lighting expert at MyJobQuote said, "A tedious task (but a money0saving one), if your Christmas lights seem to be disconnected, ensure that each bulb is fully in its socket. 

"Just one loose connection can break the whole circuit. Lights that hold 50 bulbs commonly work on 2 circuits, meaning that one loose bulb will break that circuit. If only half of your lights are working, this indicates a loose bulb."

Check for loose connections and if you can see any, try and push them down onto the power connection properly to see if that fixes the problem. 

2. Blown and tired fuses

Next check your fuse. Inside your lights there will live one or multiple small fuses and if one overheats and blows, it can cause one section or even the whole string of lights to stop working.

Goodman explained, "You may be able to recognize a blown fuse by sight alone. If the metal filament inside the glass cylinder of the plug has a break, this is a blown fuse. A break appears as a visible gap within the wire or as a dark smear within the fuse itself."

You may have been provided with an extra fuse on buying your lights, but if you weren’t (or they’ve ended up rolling around somewhere in the random stuff drawer in the kitchen) you should be able to get one from a hardware store. You can even purchase them online if you know which type you’re looking for. But they are simple to replace.

How to replace the fuse:

• Open the plug’s latch with a small screwdriver (any that you’ve collected from last year’s luxury Christmas crackers would work perfectly!)
• Use a fuse tester to figure out which is the one causing the problem
• Carefully take out the faulty fuse and replace it with the new one
• Screw the latch back onto the plug and you should be good to go!

3. Broken lightbulbs

If all of your lightbulbs are connected properly and the fuses are all working/have been replaced for new ones, then chances are the issue could be that your lightbulbs themselves are broken.

When it comes to how to fix Christmas lights in this instance, you may think this means you need to splash out on a whole new set of lights. But it's not necessary—you can just replace a single bulb. Replacement bulbs are actually super easy to get hold of—again, either from your local hardware store or online. If you're not sure which type of bulb you need, bring your lights with you and ask an expert in the store.

The best way to go around this fix is to first check which bulb it is that’s causing the problem, as just one can cause a large section to go dark. Use an electrical tester to identify which bulb is the broken one. Then simply pick out your broken bulb and clip in the new one.

4. Chewed or mangled wires

Most of us can probably admit to storing our Christmas decorations in tattered old boxes that we keep in our cold attics or garages, or even outdoor sheds. And even the best Christmas decorations can be subject to wear and tear over time. So chances are that are precious Christmas lights are actually left subject to whichever animals want to get them.

This can lead to finding chewed wires when you open up your Christmas decor box, which, in all honesty, can be quite dangerous. Goodman explained, "45% of Christmas tree fires are caused by chewed wires. If wires are exposed, do not wrap them in electrical tape, instead, dispose of them correctly." 

In this case, it’s probably better to abandon ship and invest in some new lights—save any Home Alone-style electric situations!

While fixing your Christmas lights yourself is generally safe, Goodman warns that you should absolutely avoid and exposed wires, and leave it to the professionals in that case.

He told w&h, "Changing a fuse is certainly safe. Any exposed wires, you must leave them alone. A single bulb is 7.5 watts, this can cause a lot of damage if misused."

And of course, if you simply don't feel comfortable, calling in a professional is absolutely fine, although you'll obviously need to be willing to part with your money for them to fix the issue.

To try and help avoid any damage to your Christmas lights this year, installing a Christmas tree skirt around the base of your tree can be helpful, as it will prevent curious hands and paws (from little ones and pets) touching power boxes. 

With thanks to Thomas Goodman, a construction expert at MyJobQuote for his time and expertise for this article.