- A top reason that indoor Christmas tree lights malfunction is an overloaded electrical circuit.
- Discard damaged bulbs promptly and replace them in order to extend the life of Christmas lights.
- Give your string lights an end-of-the-season check-up to prevent future lighting problems.
- Visit Insider's Home & Kitchen Reference library for more stories.
Lighting and trimming an indoor Christmas tree is one of the most treasured — as well as potentially troublesome — holiday traditions. If part of that tradition is the inevitable failure of a strand of lights, there are a few easy solutions you should try before you toss them into the trash.
Below, Eddie Bello, owner of Illuminations Holiday Lighting, and Gary McCoy, store manager for Lowe's, walk us through how to troubleshoot Christmas light issues, so you can look forward to a bright holiday season.
1. Check the circuit breaker
When to try it: When none of the lights work.
If none of the bulbs in a string of Christmas lights work, and you also notice that other lights in the same section of the house go out, you've likely tripped the circuit breaker, says Bello. An overloaded electrical circuit — a situation where more electrical demand is placed on an outlet than it can handle — is the most common (and least serious) reason for this, he explains.
To check the circuit breaker, plug the lights into an electrical outlet. Next, reset the circuit breaker. To do this, locate the labeled circuit in the metal circuit box panel, which is usually found in your home's utility room, basement, or garage.
Once you locate the circuit you believe is tripped in the panel, move the switch all the way to the "off" position, and then to the "on" position. You can often tell which circuit was tripped because the switch will be slightly out of alignment with the others.
If the bulbs light back up, an overloaded and tripped electrical circuit was likely your problem. This is good news, and you don't need to do anything further, other than taking care not to plug in multiple high-voltage electrical items simultaneously in the same area of the house.
2. Replace the fuse
When to try it: When the entire string won't light up
"If you have power coming from the outlet but your lights are not illuminating, it could be the result of a blown fuse," says Bello. Replacement fuses are often included when you purchase lights, but you can also buy them at most stores carrying holiday lights, says Bello.
To replace the fuse, slide open the lid on the back of the plug that inserts into the outlet. If the fuse is blown, one of the fuse tubes will likely appear black in color or have visible burn marks, he says.
Take a small tool, such as an eyeglass screwdriver, and pry out the fuses. Then, gently press in the new fuses. Close the cover, plug the lights in, and they should work.
Bello notes that if the fuse blows again, it is likely due to damage in the light strand. If this happens, he says you should discard the lights and replace them.
3. Replace burnt-out bulbs
When to try it: When individual bulbs or parts of the string won't light up
If the fuse isn't the problem, there is probably a problem with a bulb, says McCoy. To fix burnt-out bulbs, untangle all string lights and check for frayed wires, damaged sockets, or broken bulbs.
Discard any damaged bulbs, and then replace them with spare ones. "Just be sure to use bulbs with the same voltage rating as the rest of your string lights," says McCoy.
4. Test bulbs for damage
When to try it: When no bulbs are visibly damaged and the lights aren't working
If no bulbs are visibly damaged, and your lights are not working, use a bulb tester, says McCoy. Follow the manufacturer's instructions to test each bulb. Once you find the faulty bulb, unplug the associated light strand from the outlet and replace the faulty bulb with a new bulb. Be sure to firmly seat each bulb in its socket when replacing it.
Give lights a post-holiday check-up
A great way to prevent future problems is to test your lights at the end of the season, says McCoy. As you take down each strand of lights, replace any burnt-out or broken bulbs. Throw away strands with broken or frayed cords. When it's time to trim the tree next year, your lights should all be working.
Insider's takeaway
Christmas light problems can quickly drain the joy out of your holiday decorating happiness. Tripped circuit breakers, blown fuses, and burnt-out bulbs are the most common problems, and thankfully, each one has a simple fix.
Before you pack your Christmas decorations away at the end of the season, give your string lights a post-holiday checkup. That way, you'll look forward to a bright and trouble-free holiday next year.