How To Fix Christmas Lights | Family Handyman

A few minutes

Beginner

$0 - $20

You know the feeling: You turn on some holiday tunes, gather the family and start to decorate the Christmas tree, only to find a bunch of half-dead lights when you pull them down from the attic. What to do? Is fixing holiday string lights worth it? Brandon Kidwell, virtual electrical expert at Frontdoor, understands what you're going through.

Luckily, it's easier than ever to fix holiday lights, and Kidwell walks us through the process. Below, we've got all the tips and tricks to get you back in the holiday spirit.

The main one is simply "age and wear," Kidwell says. "Over time, materials can degrade." This is why Christmas lights are classified under "temporary installations" in the National Electrical Code (NEC) — the materials in your typical big-box light string just aren't made to last forever. So, don't leave your lights up year-round. (The NEC restricts it to 90 days, tops.)

Here are some other reasons holiday string lights break:

But, while holiday lights "can break for various reasons, there are effective ways to prevent damage and ensure they last longer," Kidwell says. Let's start by fixing Christmas tree lights, then Kidwell will walk us through proper upkeep so you can be confident your lights will work every time.

Fixing Christmas tree lights is a fairly straightforward, safe process, but it's important to be careful with electricity. When swapping out fuses, unplug the string from the wall. And don't stick your finger or anything metal into the sockets. Frayed wires are a shock hazard, so if you find exposed wires from friction or rodent activity, it's best to replace the entire string.

To make sure you're getting high-quality, safe products for troubleshooting and fixing Christmas tree lights, look for the listing mark by UL (or another testing and standards organization like Intertek) when buying lights, tools and materials.

Depending on what problems you're having, you'll need a non-contact voltage tester and/or a specialized Christmas light tester that works on incandescent and light-emitting diode (LED) light strings. If you have to replace a fuse, you'll need a flathead screwdriver.

Have on hand extra Christmas light bulbs and fuses, available inexpensively at your local home center.

Incandescent lights were the norm for Christmas lights for decades, but newer LED lights last longer and use less energy. If you’re using a Christmas light tester, it matters which kind you have because the testers are not always dual-use.

“Most [Christmas light] testers work well with incandescent lights since they operate on a simple filament-based system,” Kidwell says. If you have LED lights, buy a tester that is made for LEDs, or use a non-contact voltage tester or multimeter, which works on any type of light.

“Many testers can also handle LED lights, but some may not detect them properly due to their lower power consumption and different electrical characteristics,” Kidwell says. “It’s important to check the specifications of your tester.”

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If the entire Christmas light string doesn’t work, try these steps first.

If the power is on but the entire string of lights doesn’t work, replace the fuses.

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Pro tip: Incandescent Christmas light strings have an internal shunt within each socket to prevent a bad bulb from knocking out the entire string. Christmas light testers often have a mechanism to fix a faulty shunt. Just insert a single socket into the tool and pull the trigger several times.

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If you don’t have a Christmas light tester, test lights the old-fashioned way. This works for both incandescent and LED lights.

If all else fails, use one good light string to test a bad one.

Not very long. Incandescent holiday lights have short life expectancies, about 1,000 to 1,500 hours. That’s about one to three seasons, depending on usage. LEDs can last 25,000 hours or more in theory, but the abuse Christmas lights take means they probably won’t last that long.

A few reasons. “If the wires are frayed, exposed or melted, it can be unsafe to use, making repairs impractical,” Kidwell says. Likewise, if you have multiple bad bulbs, and replacing them doesn’t help, or the lights are old and inconsistent, it’s probably not worth your time to figure out.

Kidwell says the basic process for fixing Christmas tree lights is the same as fixing Christmas string lights. Check the power source and fuses, look for damage, check connections and test individual bulbs with a tester.

Hopefully, after reading this, you do! But if that doesn’t work, or you have expensive lights and decorations that you’re not confident troubleshooting, call an electrician. Another idea is a sprinkler supply store. Strangely enough, sprinkler stores sell professional-grade Christmas lights and can help you troubleshoot or possibly even fix them for you.

Brandon Kidwell is an experienced electrician and virtual electrical expert at Frontdoor, a home service and maintenance app that connects qualified, on-staff experts to homeowners via enhanced video chats.