Reindeer: That's an interesting question. To replace a fuse on Christmas lights, you'll need to follow these steps. First, you'll need to unplug the Christmas lights from the power source. Next, you'll need to locate the fuse box, which is usually located near the circuit breaker. Once you've located the fuse box, you'll need to identify the fuse that needs to be replaced. Finally, you'll need to remove the old fuse and replace it with a new one.