how to find bad christmas light bulb

To find the bad Christmas light bulb, first, identify the strand of lights that isn't working properly. Then, look for any obvious damage, such as broken bulbs or frayed wires. Next, check each bulb individually by removing it from the strand and testing it with a multimeter. If the bulb is not working, then you've found the culprit! Replace the bulb and you should be good to go. If the lights still don't work, there may be a more serious issue with the strand, and it may need to be replaced.