Christmas Tree Lights Troubleshooting & Repair Guide
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If you have a set of Christmas Tree Lights that are giving you problems and not working you will have to do something called troubleshooting. Most sets of Christmas lights can be repaired easily, but sometimes it will be just better to replace the strand of lights. There are also two different types of Christmas Tree Lights, you will have two strand and three strand wires. The lights with the two strand wires will all go out when one bulb goes bad compared to the lights with the three strand wire.
Most of the time the fuse or one of the bulbs has gone bad causing your set of lights to partially work or even not work at all. Replacement Christmas light bulbs and fuses will usually be included with the packaging when you bought them. Most of the time there will be a small clear plastic bag that is taped to the end of the light string near the plug and inside this bag you will find a few extra fuses and bulbs. Some brands will also include a flasher bulb so you can have your lights flash.
How To Replace The Christmas Tree Light Plug Fuse
On the plug of your lights you will have a fuse that will protect the circuit if it overloads or there is a power surge. Each brand of Christmas lights is different but most of the time you will have to use a small screwdriver and pop out a little tab. Once you pop the tab open on the plug that is on the end of the light string you will be able to remove the fuse. The fuse will just fall out if you turn the plug upside down so that the fuse opening is facing towards the ground.
Once you have removed the old fuse you will want to take your new fuse/s and slide them into the opening. Now that the new fuses are in place you will want to shut the tab on the plug. If you have replaced the fuse on your light string and your lights still are not working you may want to make sure the outlet you have them plugged into has power. You can test this by plugging in a string of lights that you know work.
How To Replace Bad Christmas Light Bulbs
When you have found out what bulb/s are bad in your string of Christmas lights or Pre Lit Tree you will now need to replace the bulb. The first thing you will need to do is to make sure that the lights are unplugged from the electrical outlet to make sure you do not get shocked. Once you are certain they have been unplugged you can remove the light bulb from the strand using a Christmas Light Bulb Puller or you can gently pull on the light bulb base and slowly wiggle it out. If you have a small Flathead screwdriver you can also take it and catch the edge of the plastic that holds the bulb into place and gentle pry it out.
Once you have removed the bulb/s that are bad you can either insert a flasher bulb in its place to make you lights blink or you can insert a new colored or white bulb depending on what will match your light string. To make sure that you are installing the new bulb correctly you will want to make sure that the two wires on the side of the plastic bulb casing are aligned with the metal inside of the light bulb socket. This will ensure that your bulb makes a good connection with the light socket so the bulb will light up when the strand has power. When you have all of replacement bulbs in place you can now test the strand of Christmas Tree Lights by plugging them back into the power source. If after you plug them in they still don’t work you should check your fuse and se if you missed a bulb. On three strand light sets the other lights should be lit and then just he bubs that are bad will not be lit making it way easier to identify which ones you will have to replace. 
How To Make Your Christmas Lights Flash
If you have a set of multi-colored or white lights and they do not blink or flash you can replace one of the bulbs with a flasher bulb. Most Christmas Trees and light sets come with a flasher bulb that can be inserted into any one of the bulb sockets and then the strand will blink. You can identify a flasher bulb because they will be clear with a small dab of red paint towards the tip of he bulb. You will fist have to unplug the string of lights from the outlet. Once the lights are unplugged you can pull out one of the bulbs and then insert the flasher bulb. Once you have replaced the bulb with the flasher you can plug the lights back in and in a few minutes the lights should begin to flash. If you want the lights to flash more you could also add a second flasher bulb in the strand.
How To Use A Christmas Light Bulb Tester
If you have no idea if your lights are bad or not you can use something they sell call a Christmas Tree Light Bulb Tester which is basically a plastic mold with a 9V battery inside. On top of this small tester will be a spot where you stick in the light bulb that you think is bad. If the light bulb is bad the bulb will not light up. If the bulb is still good you will see it light up because inside of the bulb tester is the 9V battery that will provide the power to do so. Christmas light bulb testers are a cost effective way to find and replace all the bad lights in your strand and will save you lots of time as well.
I got a set of christmas deer with lights from my inlaws. When I replace a broken light and plug them in the light keeps popping. It has been very fustrating how do I stop this from happening?
You might be using replacement bulbs of the wrong voltage. Buy a pack of 2.5 volt bulbs and a pack of 3.5 volt bulbs. The bulbs usually come 10 to a pack for under $1.50. Try one of each. I’ve seen bulbs of 1.5 volts, but they are hard to find in stores. Check for debris in the base too.
I have a 3 strand set of lights on a spiral tree that none of the lights burn. I have checked the fuses and they are good–anyone have any thoughts as to what the problem is?
This seems like an old site …but I will post anyway. I have one set of 150 mini lights in the tree. The other day there was a thunder storm. Before I even heard it or saw lightening the lights in the tree went out so I don’t know if it was just coincidence. I tried to plug it in to a socket I know is working, tried both through extension cord (which was initial setup) and without. I tried changing the fuses with 2 sets of new fuses. No change. What is happening is that when I put the lights in the socket, they all come on for a split second, and then complete darkness. What could be happening? I don’t have pets and don’t see any cuts on the part of the strand that is visible below the tree.
M.S., Same response I gave to berdo above: You might be using replacement bulbs of the wrong voltage. Buy a pack of 2.5 volt bulbs and a pack of 3.5 volt bulbs. The bulbs usually come 10 to a pack for under $1.50. Try one of each. I’ve seen bulbs of 1.5 volts, but they are hard to find in stores. Check for debris in the base too. An item called “Light Keeper Pro” ($20.00+/-) is a great tool to fix mini light problems, most of the time.
Thank you but I replaced the fuse with the ones from the original box. When I initially plug in the lights they stay on for about a second and then it’s all dark. I actually don’t see anything wrong with the fuse but replaced them anyway. Per the box it should still work even if one light is out. I just don’t understand why they would all come on right when I am putting the plug in the outlet. This can be repeated endless amount of time. The lights will all come on, for a second, and then go out.
I got an idea why don’t we all just send china a couple hundred bucks a year to quit sending their crap here!
Daniel is sooooooo RIGHT!!!
This site really helped me out! THANKS!
0ur 80 LED set of tree lights,made in China lasted 3 days.They were bought to replace the original set of 40 push-in bulbs which lasted 10 years and were made in Malaysia.
Okay, I had a strand of lights on my pre-lit tree blow out. All of the blubs had black residue in them. So, I went searching for 2.5 volts light replacements. HARD TO FIND. I finally went to the store and bought a string of lights and took the bulbs out and replaced my burnt bulbs from my tree. Half way through replacing them. The lights came on and stayed on except the ones I haven’t replaced. I was so thrilled. I continued to finish the replacing of the bulbs. At the end I turned on my tree and now that strand is blinking. Can you tell me what had happened? I know that I didn’t put in a flashing blub, the clear bulb with a red tip. ANY HELP WILL BE GREAT!!!!
Some blinker bulbs aren’t red-tipped. Actually, here in Europe red-tipped blinker bulbs are mostly an exception, not a rule!
Try figuring which one of the newly put bulbs is the blinker by looking at them. Blinkers have what seems to be three metal “parts” inside, while regular bulbs have just two wires supporting the filament. The blinkers simply look “different”.
I have several strands of the Phillips white lights where only half the strand lights. The last half of the strands are out. Anyone know why and how to fix this problem?
Okay….maybe somebody can help here! I have a pre-lit artificial tree with approx. 400 lights. ( 8 50 light sets?) I have had 1/2 of a set go out twice! After troubleshooting them on the tree it seems that the culprit is a bulb that has white paint on its tip and I don’t think it lights up! Can anyone tel me what this bulb is? When I replace it with a regular bulb, the set works again! Thanks!
I have an LED Feeding Doe on my outside Christmas setup. It keeps blowing fuses as soon as its plugged in. I cannot see any bad wires or physically see a bad bulb. Any ideas? Thanks.
We have a prelit LED Christmas tree with 650 lites, half of the very bottom ring of branches
no longer lights up, what do we do?
I have a pre-lighted Christmas Tree , I”ve had the tree for several years.with no issues, as of right now, the tree lights as it should but for some unexplained reason my 15 amp fuse keeps blowing.? I”m not overloading the curcuit. Never had a problem before. Any sugestions.
I have a prelit tree several years old never had a problem that light keeper couldn’t fix until now. Entire string went out light keeper didn’t fix. Checked fuses they are OK. Started checking bulbs and found over 20 burned out until the string lit again. When they lit they were super bright and only stayed lit for 5 minutes. Please help!
I have one of the older wire outdoor Christmas trees where the lights are attached to the wires (can’t be taken off). Because it is so old, most of the lights are blown on it. The tag on the strands states that we must use 3.0 volt mini bulbs. I can’t find those anywhere! What can I do to save this tree…they don’t make them like this anymore and even ones close to it are $300! : (