How to Repair Christmas Lights

You're not crazy—those lights did work last year. Christmas string lights often burn out the moment you unplug them, meaning you might not notice there's a problem for months. We're here to help! First, we'll explain how to figure out what the problem is, then we'll walk you through how to fix it so you can light up this holiday season!

How can I fix Christmas lights?

Replace dead bulbs by pulling out the bulbs with your fingers or a Christmas light repair tool, then pressing fresh bulbs into the empty sockets until you hear a click.
Replace blown fuses by sliding open the slot compartments in the male end of the plug, removing the fuses, and placing new ones in the slots.
Repair the shunt by removing a dark light bulb from its socket and plugging the socket into a Christmas light repair tool. Then click the repair tool at least 20 times to close the shunt.

Section 1 of 5:

Troubleshooting Broken Christmas Lights

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If only a few or half of the bulbs are dark, the issue could be a loose bulb connection, a malfunctioning shunt, or dead bulbs. If the entire string is out, the fuse is probably broken and needs to be replaced.
Unplug the Christmas lights and then turn each dark bulb clockwise and press gently down on it to ensure it's secure in its socket. If you hear a clicking sound, that means the bulb was loose and that you just pushed it back in place. After tightening all the bulbs, plug the string back and in and see if that repaired the issue.

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Test for dead incandescent light bulbs with a Christmas light repair tool. You can use the Christmas light repair tool to evaluate the individual bulbs in a dark section of string and identify the point where the current is failing. ^{[1]
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Research source} Follow these steps to use it safely:
- Place the repair tool between the wires coming out of a light bulb socket that's gone dark and press the trigger.
- If the tool hums or lights up, the current to that socket is live. Keep testing sockets until you come to one that doesn't cause the tool to hum or light up. That's the dead bulb you're looking for.
- Replace the dead bulb and see if that fixes the problem.
Plug the string of lights into the wall and hold the pen up to each dark bulb in the string. The non-contact voltage detector will beep if it detects a live current. If it doesn't beep, you've found a dead bulb and need to replace it. ^{[2]
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Clear the shunt to find out which bulbs are dead. Christmas lights are connected in a series, meaning a section of it will go dark when one bulb fails. A failsafe called a shunt in each bulb is supposed to prevent this by closing the gap across the burnt-out bulb, but it often doesn't work properly. To identify the dead bulbs quickly, try clearing the shunt with a Christmas light repair tool. ^{[3]
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- Plug a Christmas repair tool into the wall along with your string lights, then remove one of the dead light bulbs from its socket.
- Plug the dead light bulb's socket into the repair tool and click the trigger at least 20 times. This will clean the shunt if it's corroded or dirty, which will allow the current to move past the dead bulb and light up the other bulbs in the string. The ones that don't light up are likely dead bulbs.
A string of Christmas lights typically has 1-2 tiny fuses in the plastic box attached to the prongs. Unplug the lights and slide the fuse slot covers out with a small, flat screwdriver. Tip the fuses out into the palm of your hand. If one of them is black or the wire inside it is broken, replace both fuses. ^{[4]
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Section 2 of 5:

How to Replace a Christmas Light Bulb (Incandescent & LED)

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Take the burnt-out bulbs to a hardware store, pharmacy, or home improvement store. Look for new bulbs that match the old ones as close as possible. Ideally, check the packaging your lights came in to see what type of bulb you need.
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Remove each of the blown-out Christmas light bulbs. With one hand, delicately pinch the broken light's plastic socket with your thumb and forefinger. Then, with the other hand, gently pull upward on the bulb to free it from the socket. ^{[5]
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- If you have a Christmas light repair tool, it may come with a small flat edge that you can use to get underneath the light bulb and pry it out of the socket.
Make sure the two copper wires on the bottom of the bulb fitting are completely aligned with the holes in the socket. Gently press the bulb into the socket until you hear a soft click. Then plug in your lights and watch them glow. ^{[6]
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Section 3 of 5:

How to Replace a Christmas Light Fuse

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Electrician Frank Boss suggests gently levering the blown fuses out with a thin screwdriver or another flat implement like a pen knife.
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Find exact replacement fuses that match the old ones. Most Christmas lights are sold with spare fuses for this purpose. If your spares have escaped from the holiday box, take the blown fuses to an electronics store and ask them to match you with new ones of the same size and voltage rating. 100-light strings typically use 3A fuses, but be cautious and confirm your fuses' rating with a store employee. ^{[7]
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- Never use a fuse with a higher voltage rating. This can cause a major fire risk in your home.
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Drop the new fuses into the slots in the fuse box. Ensure they're fully inserted, then slide the slot covers back into place and plug the lights into an outlet. If most or all of the lights turn back on, the fuse box is fully repaired. ^{[8]
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- If the lights still won't come on, try a different outlet in case you blew a house fuse or circuit.

Section 4 of 5:

When to Replace Your Christmas Lights

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If the string light wires show obvious signs of wear and tear or water damage, the best solution is to throw the lights out and buy a new string. Replacing wires is a challenging task, especially for non-electricians.
If more than one light bulb socket is broken or smashed, buy new string lights. Replacing or removing the sockets would involve cutting the wires and twisting a cap on top, and at that point, it would simply be easier to get new lights altogether.
If you have trouble using a voltage detector or a Christmas light repair tool to find where the current disconnects in the strings, it may be better to get new lights. Boss says replacing it is usually "the safer course of action."

Section 5 of 5:

How to Properly Store Your Christmas Lights

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This keeps the wires and bulbs from tangling up and lets you store the lights without taking up a lot of space. You can also purchase a cord wind-up or a reel, which will hold the string more securely than a piece of cardboard. ^{[9]
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Insert one end of the string through the roll, then secure it with some tape. Then start wrapping the rest of the string around the roll, starting at one end and making your way to the other. When you reach the edge of the roll, tape the other end of the lights in place, as well.
Pick up one end of your lights and wrap it around your elbow and then up over your hand. Repeat this movement until the entire string is coiled around your hand and elbow. Remove it and wrap a wire or fabric tie around the middle of the coil to hold it together. Then store the string lights in a bag with other lights or by themselves. ^{[10]
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Community Q&A

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Question

What do I do if it appears my whole set has blown, but the fuses are still good?

Community Answer

Check the entire wire, beginning at the plug, for a shunt interruption using the red gun. Read the instructions carefully; they seem very complicated at first, but become intuitively clear as you become more familiar with it. At the first interruption, replace the light bulb. Continue to do that all along the way. Eventually, one replaced bulb may light up the whole set.

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What do I do if I cannot remove the dead bulb from the original socket to replace or test it?

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Use a thin knife blade to remove the bulb holder from the socket. Then you can remove the bulb from the holder.

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Why does the whole set of lights burn out when just one light burns out?

Community Answer

The lights are connected in a series circuit, so if one light burns out the, metal inside isn't conductive anymore. This means that the energy can't go past that piece of metal, which results in everything burning out.

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Tips

Before discarding a damaged string, remove the working bulbs to use as spares.

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Every year when taking out your lights for reuse, always inspect the strings for damage before connecting them to power. Do this under good lighting conditions so you can easily see frayed or chewed cords, burnt-out bulbs, bad connections, etc.

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Replace all burnt-out string light bulbs in the comfort of your living room before hanging them outside.

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Warnings

Hang sections of lights while they are disconnected from a power source, and briefly check periodically as you go to prevent accidental shock.

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Use light strings outdoors only if they're labeled for Outdoor or Indoor/Outdoor use.

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If a string light cord has damaged insulation with visible copper wire, do not use the lights.

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Use non-conductive supports designed for light strings to prevent the accidental energizing of metal gutters, downspouts, railings, trim, etc.

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Electrical outlets on the exterior of homes should have weatherproof bubble-like covers that prevent water from entering even while a cord is connected.

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Things You'll Need

Troubleshooting

Christmas light repair tool or non-contact voltage detector

Bulb Replacement

Replacement bulbs
Christmas light repair tool

Fuse Replacement

Flathead screwdriver
Replacement fuses

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How to Repair Christmas Lights

How can I fix Christmas lights?

Steps

Troubleshooting Broken Christmas Lights

How to Replace a Christmas Light Bulb (Incandescent & LED)

How to Replace a Christmas Light Fuse

When to Replace Your Christmas Lights

How to Properly Store Your Christmas Lights

Community Q&A

Video

Tips

Warnings

Things You'll Need

Troubleshooting

Bulb Replacement

Fuse Replacement

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References

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