How to Fix Christmas Lights: Top Tips for Troubleshooting, Repair, and Care

Hunting for Christmas light fuses that are broken and replacing bulbs can be incredibly frustrating. But with these tips, you'll be fixing Christmas lights—and saving your holiday display—in no time. 

By Tom Scalisi | Updated Nov 23, 2022 3:00 PM

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How to Fix Christmas Lights

If avoiding frustration and preserving your holiday spirit are at the top of the wish list this holiday season, learning how to fix Christmas lights that are on the fritz might not be worth the time. It can be a discouraging and sometimes fruitless job; one seemingly fit for the North Pole’s top electrician. But if you are up to the challenge, white (and colored) lights may be waiting for you at the end of the (proverbial) Christmas tunnel.

Read on to find out the most common causes of, and the easiest solutions to, problems with Christmas lights. Note that for your own safety, before attempting to fix Christmas lights, it’s essential that you check twice to be certain your string lights are unplugged.

Troubleshooting Christmas Lights

String lights can fail for a great many reasons, but with this guide to troubleshooting and repairing Christmas lights, you’ll soon be able to identify your string lights’ issues. Learning how to fix Christmas lights that don’t work is something of a lost art, but knowing how could save your holiday festivities.

Verify That the Outlet Has Power

There are a few different ways that a string of Christmas lights can go kaput, and it’s worth starting at the simplest cause first when fixing Christmas tree lights. If you plug in a string of lights and they aren’t working, ensure there is power at the electrical outlet first (if you don’t have a pen tester, plug in another string of lights). If there isn’t any power at the outlet, check for a switch first before heading to the breaker box.

Check for a Blown Christmas Light Fuse

The most obvious things to check next are the fuses. In most Christmas lights, fuses—two of them on each light, in fact—are hidden behind a sliding door in the plug. It can be hard to tell if they’re any good, but if they pop, the Christmas light extravaganza will be delayed.

how to fix christmas lights

The Problem Might Be Down to the Wire

If the string doesn’t light with fresh fuses in the plug, the issue is either a bulb or an internal break in the wiring. Keep reading to learn more about these issues and what you can (and can’t) do about them.

How to Repair Christmas Lights

Repairing Christmas lights can be a thankless job, but if Walmart is sold out of lights for the season and you have to make do with what you have, fixing a strand or two might be a reality. The following tips will explain how to repair Christmas lights (without you having to do your best Clark Griswold impression). Just be sure to have a hot cup of cheer nearby; you might need it.

How to Replace a Christmas Light Bulb

The circuitry of holiday lights is often such that every bulb must be functional for the current to run the full length of the string. Just as one rotten apple spoils the basket, a single burnt-out bulb compromises all others on the string. Finding the culprit can be a tedious job, so use a multimeter to make quicker work of locating the point at which the current is interrupted. Once you’ve identified the busted bulb, simply replace it with a new one to restore your festive display to its bright, shining glory. Replacement bulbs are readily available at hardware stores, home improvement centers, and via online retailers.

how to fix christmas lights

How to Change a Fuse in Christmas Lights

If you have an older string of holiday lights that won’t turn on at all, you might be able to blame the fuse. This is so common a malfunction that many holiday light kits come with a replacement fuse. If your kit didn’t, or if you’ve long since lost the replacement, it’s possible to buy a set of replacement fuses.

Learning how to change a fuse in Christmas lights is easy—there’s no need for a solderer or special tools. The fuses hide in the male-side plug behind a small sliding door. To change a fuse in Christmas lights, first unplug the string of lights from the outlet. Then simply slide open the little door on the plug, carefully remove the old fuse with a small screwdriver, and then insert the new one.

RELATED: Buyer’s Guide: The Best Indoor Christmas Lights

Lights Won’t Stay On? Use a Splitter 

Christmas lights are tailor-made to be strung together, but if you link too many in a chain, all of that holiday spirit can overwhelm your electrical outlet. If you suspect overzealousness may be the root of the issue you’re facing, try dividing the lights among two or more outlets.

Another option is to purchase a holiday light splitter, a handy accessory that evenly distributes electrical current. A splitter enables you to add more strings to your holiday display when you don’t have multiple outlets.

Fixing Flickering Christmas Lights

If your lights are flickering, the electrical outlet may not be able to handle the wattage demands of your design. Have a look in your breaker box and check the amp capacity for the outlet in question. Your maximum wattage is the amp value shown, multiplied by the number of outlet volts. If you have, in fact, maxed out the juice on your outlet, cut back your display, or supplement it with solar-powered Christmas lights. Solar lights require zero electricity, so you can use as many strings as you like.

how to fix christmas lights

Caring for Your Christmas Lights

By the end of the holiday season, Christmas lights go from harbingers of cheer to a chore to clean up. If you want to avoid damaging your lights while putting them away, follow these tips:

  • Save the boxes and reuse them at the end of the season to protect the individual strands.
  • Don’t wrap Christmas lights into tight balls. Instead, purchase a Christmas light reel to keep them organized.
  • Use plastic light hangers instead of staples when attaching lights to your walls or siding. Staples can pinch wires and cause future issues, and they’re harder to remove.

Proper Usage And Care of Christmas Lights During the Holiday Season

Unlike fixing Christmas lights, maintaining them is pretty straightforward.

Be sure that you’re using the right types of Christmas lights light for the situation. For instance, indoor-rated lights aren’t weather resistant and can’t take the cold temperatures of outdoor applications. Outdoor lights will work indoors but they’re more expensive, so use indoor lights inside and outdoor lights outside.

All lights, regardless of the type, get warmer the longer they’re on. For that reason it’s best not to leave holiday lights on all day or overnight, regardless of whether it’s indoors or out. Utilizing a timer or a smart plug with a programmable app will help moderate usage. Also, be sure to keep the Christmas tree well watered to prevent it from becoming a safety hazard.

RELATED: Buyer’s Guide: The Best Outdoor Christmas Lights

Storing Christmas Lights in the Off Season

The most important thing you can do when storing Christmas lights is to avoid winding them too tightly. This can break wiring, crack bulbs, and cause the wires to tangle when you unwind them next year. Again, a Christmas light reel will help you wrap them neatly so they’re easily tucked in a storage bag. There are also other handy ways to store Christmas lights that take just a bit of creativity.

Also, store Christmas lights in the attic, basement, or garage away from other items. If you’re constantly stepping over a set of lights or walking around them, you’ll eventually damage them by stepping or dropping something on top of them.

RELATED: The 6 Best Ways to Recycle Christmas Lights

how to fix christmas lights


You might be feeling a bit more enlightened about how to repair Christmas lights, but some new questions might also be popping up. This section aims to answer those queries, as it’s a collection of some of the most frequently asked questions about how to fix Christmas tree lights.

Q. Can you string too many Christmas lights together?

You can absolutely string too many Christmas lights together, but how much is “too many” depends on a few factors. First, LED lights use far less electricity and can be safer to string more lights together (emphasis on can), but you should ALWAYS follow manufacturer directions. Five sets of lights is usually the maximum number you should connect.

Q. Why is half my light string flashing on and off?

The answer might frustrate you, but this typically occurs when a string of lights stops working and someone finds the bad bulb and replaces it. The issue is that the bulb was replaced with a flashing bulb, so that bulb will have to be found again and then removed. Happy hunting!

how to fix christmas lights

Q. How many lights can be on one breaker?

The answer is incredibly complicated and requires some electrical math, so let’s simplify it as much as possible. First, check the Christmas light package to determine how much wattage each string uses.

For a 15-amp breaker with nothing else plugged into it, don’t go over 1,400 watts. So, divide 1,400 by the wattage of the light string to determine how many you can use. For a 20-amp breaker with nothing else plugged into it, you can go as high as 1,900 watts using the same formula.

Q. Can you shorten a string of Christmas lights?

It’s possible, but it takes a bit of investigation. Most Christmas lights are wired in series, and there are several series throughout the strand. The best way to shorten these lights is to cut between two series, or where only two wires exist (as opposed to three, which each series has). Simply unplug the light string, cut these two wires, and use wire nuts to cap them off. Beware that if you shorten your lights, you could risk causing an electrical fire or shock, so it really isn’t advised.