Replace the fuse Most new packs of Christmas lights come with a replacement fuse—which should give you a clue as to how common fuse problems are with these things.

For those of us not quite as skilled in the electrical trade, here are some common problems with string lights and how to solve them.

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.

Lighting up Christmas: The quick fix for broken light sets The LightKeeper Pro, from Ulta-Lit Tree Company, is a tool that repairs most sets of malfunctioning miniature Christmas lights.

How to fix broken Christmas lights Don't waste a light strand or risk using a broken one. You can fix it.