It’s about this time of year that Christmas lights start to create problems – at least, those that are more than a year old and have been stored gathering dust somewhere. There are a number of reasons why Christmas lights fail but they generally boil down to two problems:
Light Bulbs – in older string lights, it only takes one little light globe to fail and the whole set will stop working. The only way to determine the problem is to check each globe. You can do a visual holding it up to a light source, or take a small strong pen light and shine it through the bulb. The other alternative is to get a new bulb and to go through replacing each globe until you find the culprit.
Transformer Problem – strings of Christmas lights require a transformer. This drops the amount of power back to a trickle, which is all the lights need to work. Sometimes, transformers die and need replacing. It is important to replace like with like. If you use a transformer that is the wrong size then you run the risk of blowing your lights or perhaps overheating the transformer and causing a fire risk.
LED Christmas lights seem to cause the least number of problems, although over time their transformer will die as well.