Things You'll Need
Small screw driver
It can be a huge disappointment to spend hours carefully attaching holiday lights to the interior or exterior of your home only to find that they don't come on when you plug them in. You might even spend hours checking and replacing the bulbs in light sets when, many times, the problem is as simple as a blown fuse. Fuses are a safety feature on Christmas lights, which protect against power surges, overloads and short circuits. If your Christmas lights aren't working, check the fuses. Replacing them is simple and can save you a lot of time and frustration.
Unplug the Christmas lights and locate the fuse panel. The fuse panel is located on the accessory plug with two prongs, commonly known as the male plug. There are a couple of different types of covers on fuse panels. One may have a plate covering the fuses, while the other may have a drawer that holds the fuses.
Open the fuse panel on the Christmas light plug. Even though the fuse panel may appear as if does not open, it will. Use a small flat head screwdriver to slide the fuse panel cover open or to slide the fuse panel drawer out.
Turn the attachment plug over to remove the fuses from the Christmas lights. In most cases, the fuses just fall out into your hand. If they do not, tap the plug gently against your hand. If the fuses are stubborn and still won't come out, it may be necessary to gently pry them out with a small screwdriver.
Inspect the fuses by holding them up towards a light. If one or both of them appear to be dark or black, the fuse is probably blown. If you're just not certain, you can confirm with a fuse tester.
Replace the blown fuses with new fuses and insert them back into the fuse panel, securely closing the cover back in place. Plug in the Christmas lights to ensure they are working properly.
As a safety feature, most Christmas lights have pre-installed fuses which limit the amount of current allowed to pass through the lights.
Packages of spare Christmas light fuses are available at most discount stores. Just be sure to purchase the proper size.
Since most Christmas light sets come with replacement fuses, replacing both fuses at the same time ensures both fuses are good.
If replacing the fuse in the Christmas lights does not solve the problem, check for bulbs that may be broken or blown.
Always unplug the string of Christmas lights before installing or replacing the fuses.
Make sure that your replacement fuses have the same voltage and amp settings to avoid fire risk.
Remove the Christmas tree light fuses carefully.
Do not replace the Christmas light plug as this presents a fire risk.