Troubleshoot Christmas Lights That Aren't Working

Posted by Aaron Farrelly on 4/11/2016 to Troubleshooting Your Christmas Lights

At our sister company Christmas Light Decorators, we install well over 1.5 million Christmas lights per year! At such a large scale, we have to be experts in troubleshooting and repairing lights that go out. Our customers rely on those lights to drive business and create holiday cheer at their various establishments. 

Today I would like to walk you through the steps we take when troubleshooting lights that have stopped working.

Step 1: Start at the Source of Power

I would say 80% of the time, the reason lights stop working is power related, not a malfunction with the lights. Rain causes GFCI’s to pop, kids think it’s funny to unplug the lights; the outlet could be connected to a timer that isn’t working properly, etc. etc. If you first check the outlet, and don’t notice one of these immediate problems, try plugging in something that you know for a fact works. This is a good way to see if the outlet is in fact passing power. We keep a small strand of light line with 1 or 2 sockets that we know work for this purpose. A voltage detector is relatively inexpensive and can help you check the outlet as well.

Step 2: Check the Extension Cords

If the outlet is working, follow the extension cords from there to the lights. If exposed, these can become unplugged, or a landscaper can accidently cut them. Make sure and follow the whole extension cord to check for cuts, and check each junction where two cords are plugged into each other. If the outlet worked, and you are now following the cords to the lights themselves, you can again use the small strand of light line to check the end of the extension cords, making sure power is passing through.

Step 3: Check the Fuses

If the outlet and extension cords check out, you have now made it to the lights themselves. The first thing we do when reaching this point, is check the fuses. You can slide the cover off the male end and usually identify burned out fuses by their milky white or black appearance. Using a pocket knife, or something similar with a small sharp point, simply pop the old fuses out, and install 2 new ones. Extra fuses can usually be found on the lights themselves, or can be purchased at your local hardware store.

Step 4: Replace the Strand

If steps 1-3 have not resulted in a working strand, the next step depends on a couple of things: Is it LED or incandescent, and how much time you have on your hands. If it is LED, the strand is likely bad, and needs to be replaced. If it is incandescent you can test each individual bulb and try to find the one that is causing the failure. However, since incandescent lights are pretty cheap, I suggest keeping some extras on hand and replacing the strand.

Before replacing the strand, I will typically test the next strand that it is plugged in to as well. That way you make sure the problem isn’t bigger than just one strand before taking the time to re-wrap. If the next strand works fine, replace the bad one, and be on your way. If the next strand is bad as well, your problem might be bigger than you think. Typically a multi strand problem is fuse related. Something is causing the fuses to blow in all the connected strands, and that is the core of your problem. You can replace the fuses all you want, but unless you remove the cause, they will continue to blow. This is where a better inspection of the extension cords and outlets will be needed.

Side Note: What type of light are you troubleshooting?

The above example assumes you are troubleshooting mini lights. Steps 1-2, and sometimes 3, hold true for C7 or C9 Christmas lighting as well, but step 4 is slightly different. If an individual bulb is bad on a strand of light line, and replacing said bulb doesn’t fix the problem, you likely have a bad socket. Sockets can be replaced, and can be purchased here: ? If the entire strand of light line is bad, your cause is power related, extension cord related, or possibly the male/female end of the light line. Check these in that order.

Taking these steps every time you attempt to repair lights will help save a lot of time. Occasionally we run into interesting issues that we can’t seem to diagnose, but those cases are rare. If you use commercial grade LED lights, problems are few and far between. Proper storage and care for your lights will help extend their lifespan as well. You also want to make sure you are using proper outlets and are following our suggestions on how many lights to plug into an outlet, which can be found here: link to dougs vlog? Being aware of these things will help your holiday lighting be smooth and trouble free.

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