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How To Fix LED Christmas Lights

Updated Dec 21, 2022

Updated Dec 21, 2022

Home > Blog > How To Fix LED Christmas Lights

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There are plenty of Holiday traditions that bring joy to the whole family. From Christmas tree decorating to lighting the menorah and all the family get-togethers, the holiday season is a time of celebrations and activities. However, all yuletide festivities can have their share of frustrations, the most annoying of which is faulty Christmas lights.  

In the past, repairing Christmas lights was time-consuming but not difficult once the faulty bulb was found. All you had to do was jiggle the socket slightly or, at worst, swap the bulb out for a new one. This problem has become more difficult in recent years with the advent of LED bulbs, which function differently from standard incandescent bulbs. While longer-lasting and more energy-efficient, LED Christmas lights can be a pain to repair. In this guide, we’ll go over how to fix LED Christmas lights and list some of the best Christmas light fixer tools available. 

First, Get the Right Tools for the Job 

Before we get into the minutiae of Christmas light repair, we first need to go over all the tools you’ll need to fix any Christmas light set. Thankfully, the tools needed to repair LED lights are inexpensive and easy to use. 

Voltage Detector

A voltage detector or volt tester is the most important tool in your holiday repair bag. These nifty devices allow you to measure the voltage running through an object, be it a wire, light bulb, or wall outlet. There are plenty to choose from, but we recommend a non-contact voltage tester like this one.

volt tester in use
Image Source: Canva

Wire Cutters

Depending on the nature of the fault, or your type of Christmas lights, you may need to cut out a diode or section altogether. To do so, you’ll need a good pair of wire cutters

Electrical Tape

In the case of loose connections or frayed wires, you’ll need an insulating, non-conductive tape to patch the damage. Your best bet is a good set of electrical tape. 

Clothespins or Small Plastic Clips 

You’ll need these for testing bulbs. Most Christmas light repair kits come with clips, but clothespins or small plastic bag clips will do. 

Wire Nut

Wire nuts are small, orange plastic caps that hold together two pieces of exposed wire. You may need these to fix strings with damaged diodes, bulb casings, or disconnected wires. 

Christmas Light Fixer Gun 

One of the more recent and impressive inclusions to the list of essential tools for home repair is the “Christmas light fixer.”  These multi-tools include everything you need to fix a string of Christmas lights in one handy device. They typically include an independent power supply, a light tester, clips, and bulb removers. The most well-rated Christmas light fixer gun we could find is this model

How To Fix Christmas Tree Lights 

guy repairing a cord of Christmas tree lights
Image Source: Canva

There are multiple ways to fix Christmas lights, which can change slightly depending on the type of lights you’re fixing. We’re going to break down ways to fix lights depending on the source of the failure, then explain the different variations for fixing those problems in each section. Furthermore, LED lights have become more common than traditional incandescent strings since they break less often, are more energy efficient, and tend to last much longer. As such, we’ll assume the lights you’re fixing are LED string lights. 

Find the Source of the Problem

After acquiring the right gear, your second step is discovering why your Christmas lights are failing. Faults in Christmas lights typically arise from one of three common sources: broken bulbs or diodes, blown fuses, or faulty wires. 

Safety Warning

Before we get into how to diagnose faults in Christmas lights, we wanted to remind you that holiday lights, especially those with faulty wires, can be dangerous when plugged into an electrical socket. Touching or cutting a live wire can result in electrical shocks, burns, and even death. Never try to cut or repair a Christmas tree light when it’s still plugged into an electrical socket. 

Check for Blown Fuses 

A blown fuse is the easiest problem to spot and fix. If your entire strand of lights is nonfunctioning, you’re likely dealing with a blown fuse (or potentially an outlet problem.) To check for a blown fuse, take a closer look at the male-end plug of the lights. You should see a small hatch, which you can open with a safety knife or screwdriver. Inside you’ll see two fuses, and if they’re burnt, they’re responsible for your failing lights. 

Check for Faulty Wires

Faulty or damaged wires can manifest in numerous ways, typically flickering or partial darkening of the strand. To check for damaged wires, carefully inspect the lights from one end to the other. Pay careful attention to where the wires connect with the bulbs’ base and casing. Often, wires can come loose or disconnect from these casings. If you spot a casing with small copper filaments sticking out of its base, or a completely disconnected wire, you’ve likely found your problem.

Check for Broken Bulbs or Diodes 

Unfortunately, faulty bulbs are the most common cause of Christmas light failures and are also the most difficult and time-consuming to diagnose. LED lights are especially hard because it’s not often the bulbs themselves that break but their socket, prongs, or diodes. LED light bulbs don’t have filaments that can burn out, so while breaks are less common, they can be harder to find. Troubleshooting light strands is a process of elimination.

Here is a quick breakdown of how to do it: 

  • Start by plugging your lights in and grabbing your voltage detector. 
  • You then want to check the nearest light to the male-ended plug to ensure power is coming into the lights on this side. Place the voltage detector on the base of the bulb socket, the casing, or the two wires going into the bulb. If you have power, you’re good to proceed. If not, remove the male-end plug, turn it upside down, and insert it the other way. This flip ensures the power flows to this end of the lights, not through the ground wire. Once flipped, if the light is still not showing voltage, you’ve found your bad bulb; otherwise, you’re good to proceed to the next step.
  • Now that you know power is flowing through the male end into your strand of lights, go to about the halfway point of your unlit lights. Check the middlemost light with the voltage detector; if it shows power, you know that the dead bulb is on the side opposite the male-end plug. If the light doesn’t show power, you know the broken bulb is on the half facing toward the male end. Mark the middle bulb with a clip or clothespin. 
  • Proceed to the end with the dead bulb. Going bulb by bulb, check for power as you go. You’ll want to find the spot where the bulbs with power meet those without power.
  • The last bulb that reads as being powered that connects directly to a bulb showing no voltage is likely your damaged or loose bulb. 

This process can be complicated, so here is a helpful video going over it in detail: 

Checking for a broken bulb with a Christmas light fixer gun is much easier, but it follows the same fundamental principles. Here is how to use one of these tools: 

  • Plug your lights into a wall outlet.
  • Take two of the clips provided with the kit and attach them to the lit lights on each end of the darkened section.
  • Unplug lights from the wall outlet, then plug them into the power cable attached to the bottom of the fixer gun.
  • Go to the centermost bulb of the darkened lights, and fit one of the wires attached to the bulb’s casing into the black hook at the fixer gun’s tip.
  • Pull the trigger – this will put a weak current through the lights, illuminating them.
  • Place additional clips on the end of illuminated sections. 
  • Repeat until you narrow down the darkened sections to a single bulb. This bulb is causing the short and will need to be replaced. 

Here is a quick video on how to use a Christmas tree light fixer gun: 

Begin the Repairs   

guy looking at a christmas tree light
Image Source: Canva

How To Fix Fuses in Christmas Tree Lights

Repairing fuses in Christmas tree lights is easy. If you have a set of replacement fuses, all you need to do is open the small hatch in the male-end plug, remove the burnt fuses, and insert the new ones. If you don’t have any additional fuses, you can pick them up at a big box store. 

How to Reattach Wires in Christmas Lights

If you spot a damaged section of wire or a wire has come loose from a bulb’s casing, you’ll need to repair it. Damaged or exposed wires, even if their effect on the lights is minimal (like occasional flickering), are a fire risk and can result in property damage or injury. Unfortunately, damaged, stripped, and torn wires along the string’s length are nearly impossible to fix. Using an electrician’s tape can temporarily make them safe to handle, but they’ll eventually bend and become loose, becoming a greater risk. Furthermore, if you cut out the damaged section and insert a wire nut, one wire would be shorter, making the entire string of lights unusable. 

However, if a wire has come loose from a bulb’s casing, you can repair it by following these steps:

  • Fully removing the wire.
  • Tighten the copper filaments into a point.
  • Reinserting them firmly into the bulb’s casing. 
  • Carefully plug in the lights, then, if the short disappears, unplug the lights again to tape the reinserted wire and bulb casing securely.
  • If the short does not disappear, you’ll need to completely remove the bulb and casing – for instructions on this, see the “How to Repair Burnt Christmas Light Bulbs” section. 

How to Repair Burnt Christmas Light Bulbs 

If your LED Christmas lights possess removable bulbs, all you have to do is pop out the broken one and insert a replacement bulb. Otherwise, you’ll have to cut off the bulb and its case (called a shunt), then attach a wire nut. To do this, you must: 

  • Ensure the Christmas lights aren’t plugged in.
  • Take a pair of wire cutters and snip the two wires attached to the base of the bulb casing. 
  • Carefully use the wire cutters to strip off the outer layer of the wire’s casing. 
  • Twist the inner copper filaments of both wires together.
  • Insert the now-conjoined wires into the wire nut. 
  • Thoroughly tape the base of the nut, and the wires, to ensure a secure, water-resistant connection. Creating a tight seal is especially important if you use these as outdoor lights.

Christmas light fixer tools also make this process easier. Most come with a small pod meant to more securely and safely hold the two wires together. To use this:

  1. Cut the wires from the base of the bulb’s shunt.
  2. Unscrew the top of the cap on the pod.
  3. Insert the wires into each of the small holding slots on the corresponding ends of the pod.
  4. Close the pod, and screw on the cap. 

Final Thoughts on How to Fix Flickering Christmas Tree Lights

Repairing Christmas lights is difficult, especially for those not used to working with electrical wires. Thankfully, with the right tools, helpful guides, and patience, your home can light up and twinkle right in time for the holidays

Remember that while new lights can last for seven to 10 years, you’ll eventually have to replace them. DIY repairs for Christmas lights are typically only worth the time and effort on more expensive or newer strands. If your lights are older, they’ll be more prone to shorts, and you’ll be better suited to buy a replacement set than fix them.

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