It’s the moment of truth every Christmas tree decorator has to face each year: When you unpack your Christmas lights, will they turn on?

If half your string of Christmas lights won’t light up, or worse yet — the entire string — don’t worry. Repairing Christmas lights is actually super easy! Watch these videos to find out how, no matter what type of lights you’re working with.

Remember: Always unplug your string lights before you start working on them! And if your string lights aren’t salvageable, here’s how to get rid of them.

How to Replace a Fuse on Any String Light (And Avoid Blowing More Fuses)

If your entire set of lights won’t turn on, or the string turns on briefly before going out, it’s likely you’ve blown a fuse. This is a super easy fix!

How to Repair Incandescent String Lights

A simple non-contact voltage tester will help you quickly find a bad bulb.

How to Repair LED String Lights With Removable Bulbs (No Fancy Tools Required)

If individual bulbs on your LED string are removable, you can use a pair of pliers to check the bulbs by hand. Because LED string lights have a different type of wiring, a regular voltage tester won’t work on them, but it doesn’t matter — broken bulbs are easy to identify when once you’ve pulled them out.

How to Repair LED String Lights With Permanent Bulbs (And a Faster Method for LED Strings With Removable Bulbs)

If you want a tool to quickly find where the current is failing, the only option currently on the market is a tool called the LED Keeper. The LED Keeper is a good tool for you if:

• You have a lot of LED string lights to repair;
• Your LED string lights have 100+ lights in them; or
• The bulbs in your LED string lights are not removable.

The LED Keeper gives you a way to find and bypass any broken bulbs in your LED string.