Why Do Christmas Lights Go Out?

Christmas lights can be beautiful! They can also be notoriously frustrating. You’ll buy a string of lights, throw them on your tree one year, then put them in a box for a year. During that year, you don’t move them, use them, or even look at them. And yet, when next Christmas rolls around, the lights… won’t work. Or some work. Or they blink on and off. Or they seem like they’re working… until they don’t.

But why won’t they work?! Christmas lights can be maddening… especially if you’re freezing outside while you try to get them to light. Inexplicable as their malfunctioning may seem, however, there is always a concrete reason why your Christmas lights won’t light up. We decided to troubleshoot the most common of those reasons by focusing on their symptoms. If you have any of the following Christmas light woes, here’s what’s happening and how you can fix it:

None of the lights will work

This is actually probably the most common Christmas light problem. Smaller strings of Christmas lights are usually wired in a single, long series. A single electrical wire passes through each individual bulb in order to complete the circuit and illuminate the lights. Unfortunately, that means if even one of the bulbs in the string is faulty, then the circuit can’t complete.

In order to get your string of lights working again, you’ll have to find and replace the problem bulb. There are a couple of ways to do that. The easiest way is to invest in some variety of Christmas light bulb tester. A tester will be able to locate any broken bulbs in your string. You can buy replacement bulbs wherever you can buy Christmas lights, and they’re easy to replace.

A section of the lights won’t work

As we explained above, small strings of Christmas lights consist of a single, long circuit. Longer sections, on the other hand, actually consist of several different circuits linked together. Electricity still flows from the source through each of the circuits, but the individual circuits complete before moving through the whole string. The same problem we described up above is still happening, but it’s only affecting one of several circuits.

You’ll probably notice that the section closest to the outlets work, but after a certain point, the rest of the lights won’t. That certain point is where one circuit transitions to the next. You can fix this problem the same way you’d fix a single-circuit string. Find the bulb breaking the circuit using your bulb tester and replace it. Once you’ve fixed one circuit, all the lights behind it should power back on.

Some of the lights won’t turn on

If only a few of your lights won’t turn on, then the earlier fixes obviously don’t apply to you. Some modern mini lights use a shunt wire that keeps the circuit intact even if the bulb burns out. If individual bulbs loosen or burn out, the rest of the lights will stay lit so long as you keep them plugged in. Luckily, this makes it easy to tell where the problem lights are; just look for the ones that won’t light up.

Individual lights usually stop functioning for one of two reasons: they’re loose or they’re burnt out. When bulbs loosen from the string, they may disconnect from their housing. All you’ll have to do in that case is tighten them a little bit. They should turn back on as soon as they’re housed properly. If the bulb doesn’t light back up, then its filament is probably burnt out. In that case, you should simply replace the bulb.

The lights blink on and off

This is a particularly frustrating problem because it might take a while to figure out. If your Christmas lights flicker on and off, it might be because of a loose or shifted wire inside a light socket. Shifted wires are about what you’d expect them to be. A wire in one of your bulb’s sockets is shifting just enough to knock the circuit out of alignment. When you jostle the string, you might knock the wire in and out of place, which makes the bulbs likewise flicker on and off.

To figure out which strand of your light string contains the blinking bulb, start by laying the string flat on the floor. Lift up one of three strands of wires making up your light string at a time. When the lights blink off, you’ll have found the problem strand. Work your way down that strand pinching the wiring directly following each individual light and rolling it back and forth. If the lights flicker as you do this, remove the nearest bulb and check the center wire inside its base.

Unfortunately, this list isn’t quite exhaustive. If these problems don’t seem to explain what’s going on with your lights, you may have a more serious concern. It’s even possible the problem isn’t with your lights at all, but with your electrical system!

Whether you need help with Christmas lights, power problems, or any other electrical issue, give Early Bird a call any time. We’ll help make sure your lights–Christmas and otherwise–stay lit all season. Happy Holidays!