How to Fix Christmas Lights

This article focuses on basic troubleshooting for Christmas mini lights and hardwired string lights that cannot be cut. To learn how to cut and customize SPT1 & SPT2 light strings visit our custom Christmas lights guide.

Click on a Christmas light troubleshooting topic below to be taken straight to that section:

Entire string not working
Half of string not working
Random bulbs not working

Lights flickering when moved
Lights dimming in a series
Damage Prevention Tips

Items you might need:

Light Tester
Replacement Bulbs
Spare Fuses

Common Christmas Light Troubleshooting Topics

Christmas Light Problem: Entire String Not Working

Possible Cause: Fuse burnt out in plug
Suggested Fix: Replace the plug fuse

Possible Cause: Loose or broken bulb
Suggested Fix: Use a light tester to identify and replace loose or burnt out bulbs. If you don't have a light tester, you can check each bulb on the string for tightness and look for visual clues, like cloudy or dark glass, to identify bulbs that need to be replaced.

Fix Christmas lights by replacing plug fuses

Christmas Light Plug Fuses

Replacement Mini Light Bulbs

Christmas Light Problem: Half of String Not Working

LED Strings with Rectifiers: Some LED Christmas lights are designed with one or more rectifiers placed along the string to help prevent bulb flickering. If part of the string is out, it is possible that there's an issue with the rectifier and the entire string will need to be replaced.

Rectifiers on LED String Lights Prevent Flickering

Example of LED String Rectifier

Christmas Light Problem: Random bulbs not working

If the light string has removable bulbs, replace any bulbs that aren't working. Most incandescent mini light strings include replacement bulbs. If you need more replacement mini bulbs, they can be found online and in some home improvement stores. If the bulbs can't be removed and replaced, the entire string will need to be replaced.

Christmas Light Problem: Lights flickering when string is moved

If bulbs are flickering when the light string is moved, this is likely caused by damage to the wiring and the light string will need to be replaced. Additionally, if you notice cracked insulation, a damaged plug, or frayed wires anywhere on your Christmas lights, we recommend replacing the entire set even if it is currently working.

Christmas Light Problem: Lights dimming when plugged end-to-end

Possible Cause: If you're plugging multiple Christmas light strings or lit decor items together end to end or with stackable plugs and some are dimming or won't turn on, it's possible that you've exceeded the max capacity of your outlet or light strings. All string lights and lit decor items have a maximum wattage capacity for end-to-end connections, and when you reach that limit you risk blowing plug fuses, tripping breakers in your fuse box, or creating a dimming effect in your lights.

Suggested Fix: If you run into any of these issues while plugging multiple lights together, check the fuses in any strings that won't light and replace them as needed. After changing any blown fuses, determine the max wattage capacity of the strings or lit decor you are using and reconfigure your end-to-end connections as needed. You may also need to reroute extension cords, so that part of your display plugs into a different outlet on a different circuit.

To learn more about max capacity for string lights, visit our Christmas Lights Wattage Guide.

Stackable Light Plugs

End to End Christmas Light Plugs

Tips to Avoid Damaging Your Christmas Lights

Troubleshooting Christmas lights that don't work also includes understanding their intended use and avoiding situations like:

installing lights with staple guns that damage the coating and wiring
exposing light set plugs to standing water on the ground or near gutters
leaving light sets displayed outside longer than 90 days
plugging outdoor light sets into plug outlets that are not GFCI rated
placing light sets near open high heat sources
ripping or yanking lights out of trees and bushes
improper installation or storage

Christmas Light Storage Tips

Properly storing Christmas lights after use will help to minimize damaged light strings and ensure your displays continue looking great through many years of use!

Store decorations in a cool, dry place.
Avoid tugging your Christmas lights to get them down. Instead take a little extra time to remove and store your lights carefully. Your future self will thank you!
Wrap lights around a flat piece of cardboard, then stack the cardboard neatly in a storage bin. You can cut a notch on each end of the cardboard to hold the end plugs of your light string or just tuck them in underneath the wound up lights.
Wrap Christmas light strings around your elbow and palm to create a neat circle, much like you would when winding up a hose or power cord. You can then put them in a ziplock bag and label the bags based on location or hang the light loops off hooks.
Label each storage bin with what it contains. This is an easy way to find what you're looking for and know exactly what is in each box for easy access.