Well, checking the fuse on Christmas lights is a pretty simple process. First, you need to find the fuse box, which is usually located in a closet or basement. Once you've found it, you'll see a bunch of different fuses in there. Look for the one that corresponds to the Christmas lights you're trying to check. You should be able to tell which one it is by the label or the color code. Once you've found the right fuse, pull it out and check if it's blown or not. If it's blown, then you'll need to replace it with a new one.