The LightKeeper Pro Fixes Defective Bulbs—and It Saved My Christmas Lights

Updated: May 06, 2024

'Tis the season to untangle last year’s Christmas lights... only to find a few bad bulbs in the mix. Don’t trash that string yet, now you can find the problem and fix it with the LightKeeper Pro.

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FHM we tried it lightkeeper proTMB studio

The LightKeeper Pro is a Christmas miracle, especially when you’ve discovered the Christmas lights you carefully packed away last year aren’t working. But before you turn into the Grinch, save the day (and save yourself a headache!) by fixing it right on the spot, thanks to the LightKeeper Pro, a holiday lights repair tool.

This clever device promises to repair your defective bulb faster than you can say, “Merry Christmas!” With a pre-lit Christmas tree that needed a little help, the opportunity to try this tool came at the optimal time. Find out how this gadget can save the day and put the merry back into your merry making.

What is the LightKeeper Pro?

lightkeeper pro and lightsSheri Kaz/Family Handyman

The LightKeeper Pro is an incandescent string light repair tool that fixes Christmas lights that won’t turn on. This lightweight plastic hand tool is shaped like a glue gun and is easy to use. The handy device comes with everything you need to get the job done, including a bulb tester, a fuse tester, an audible voltage detector, 10 replacement bulbs and a storage compartment.

We Tried It

LightKeeper Pro

Don’t waste your Christmas shopping budget on new lights. The LightKeeper Pro finds the problem bulb and fixes it.

How It Works

This multi-functional light repair tool kit tests and repairs many common problems with incandescent string lights. The quick-fix trigger finds and repairs the damaged shunt by sending a pulse of electricity through the strand. It basically fixes the shunt with the pull of the trigger. And the quick-fix trigger also works with the AC plug connector. Better yet, the manufacturer offers a lifetime warranty on the LightKeeper Pro. What more could you ask for?

How We Tested It

white christmas tree without some lights workingSheri Kaz/Family Handyman

I started my test with a short string of red incandescent lights that I love to string across a shelf for the holidays. Unfortunately, the string had four non-working bulbs.

The LightKeeper Pro was super helpful for extracting the bulbs. After removing each offender, I tested it with the tool, and none lit up. Next, I tried the sockets of the empty bulbs. They were burnt out. Ugh. If you’re like me, you’ve probably long lost the extra bulbs that came with the set. So, I tried the extra bulbs in the kit to bring them back to life. 

The extra bare-wire bulbs didn’t have a socket base, so I threaded the tiny wire into the old base and popped it back in the string. No luck. I’m sure there’s an art to this, so I tried again. Later, I discovered the trick to success is simple: Once the tiny wires are in the proper holes, they need to be folded back onto the green base before the bulb will work. I’ll admit, this was a tedious process that probably would have been easier with a magnifying glass. In the meantime, I found a partially working set of blue bulbs and extracted four bulbs to replace the burnt-out ones. Everything worked!

The partially working blue string no longer worked until I plugged it directly into the tool to test the quick-fix method. I gave the trigger 20 pumps, then plugged the lights into the electric socket, and voilà! It magically turned on. 

Last Christmas, my beloved pre-lit artificial tree ended the season partially lit. For the most important test, I dug the tree out of the basement and hoped the LightKeeper Pro could save it. The voltage detector gave me a steady beep until I reached the dead zones. On closer inspection, I realized the non-working clear bulbs were black, indicating they were burnt out and would need to be replaced. 

I’m sad to report that I haven’t found replacement lights with a base that fits in the sockets of my pre-lit tree. Naturally, I’d prefer to replace the entire unit rather than spend my time tediously threading bare-wire replacement bulbs. The moral of that story is to save the extra bulbs that come with the tree.


  • Works on pre-lit trees, icicle light sets, wreaths and garlands
  • Fewer tossed lights means less environmental waste
  • Replacement bulbs included
  • Affordable
  • No assembly required
  • Lifetime warranty


  • Doesn’t work on LED lights
  • Audible voltage detector makes loud beeping noise


using the light keeper proTMB studio

How do you use a LightKeeper Pro bulb tester?

This repair tool has two different ways to repair inoperable lights. With the quick-fix method, remove any bulb from the unlit strand. Next, plug the LightKeeper Pro into the light set and pull the trigger. This sends a pulse through the light set, locating the faulty bulb and fixing its shunt.

If that doesn’t solve the problem, use the included audible voltage detector, which lets you see where the electricity has stopped flowing. Lay out the light strand and run the LightKeeper Pro back and forth across the strand. A continuous beeping sound detects voltage, and when the beeping stops at a certain bulb, that signals an electrical flow issue. Next, remove the bulb in question and plug it directly into the tester. Once the bulb lights up, add it back to the light strand and you’re good to go!

Does the LightKeeper Pro work?

Yes, the LightKeeper Pro works to find and repair most outages. The bulb tester proved reliable in my testing and worked like a charm using the AC plug connector. The voltage detector gave me a good report of the outages, and although finicky at times, it was especially useful when inspecting my pre-lit tree. The light repair kit can’t fix every strand, depending on the age, quality and damage to the light string, but it can definitely tell you whether it’s worth fixing. And in most cases, the LightKeeper Pro fixes the problem quickly with the quick-fix trigger.

Can I use the LightKeeper Pro on LED lights?

The LightKeeper Pro only works on incandescent string lights. However, the manufacturer also makes the LED Keeper for your LED string lights.

What Others Reviewers Had to Say

With over 5,200 five-star ratings on Amazon, the LightKeeper Pro is busy at work saving people’s holiday lights.

Verified purchaser, Dean Quick, writes, “I recently bought this because when setting up lights for this year I found several strands were out, including some on my pre-lit artificial Christmas tree. This tool DID FIX several strands of lights using the squeeze-trigger feature. Like others have reviewed, it was like magic. I was skeptical about this quick-fix feature when I bought this, but I just pulled the trigger a few times and the strand of lights came back to life. I was on the verge of putting my artificial tree out with the trash, but this salvaged it by fixing an unlit strand. So, the tool has already paid for itself in my book.”

“I typically do not write reviews unless a product is exceptional… exceptionally good or exceptionally bad. This product exceeded my expectations and is the BEST $25 THAT I HAVE EVER SPENT!!! I would give it 10 stars if that was an option,” shares Amanda, a five-star reviewer.

“Incredible gadget—it worked quickly to resolve multiple issues!!” writes Dave, a verified buyer. “Sounds like a fix-it tool that is too good to be true right? Well, it is true and the LightKeeper Pro does everything they say—it made our old artificial tree look brand new again. $20 well spent for a great tool that will likely get more use in years to come. A+ for sustainability, too!”

Final Verdict

using the light keeper proTMB studio

The LightKeeper Pro tool detected outages in my pre-lit Christmas tree, and I was able to repair two strings of lights using working bulbs from other strings. The bulb tester function and the extracting tool are helpful, and the quick-fix trigger is amazing. Changing bulbs is a tedious process, but that’s not the fault of the LightKeeper Pro. Using this tool is actually a time saver.

I found the manufacturers’ videos to be very helpful, even though the LightKeeper Pro comes with detailed instructions. For me, the process wasn’t intuitive and the learning curve was a little time consuming. However, I’m glad I tried this gadget, because in the past, I would have thrown the non-working lights into the landfill. With every problem I solved, the more I loved this useful tool. Having decorated many Christmas trees professionally, the LightKeeper Pro tool is a valuable item in your holiday-decorating toolbox.

Where to Buy the LightKeeper Pro

The LightKeeper Pro is available for under $30 on Amazon. It’s also available at Walmart, Ace Hardware and The Home Depot. When it’s time to light up this year’s tree, get yourself an early Christmas present and say goodbye to holiday light woes.

We Tried It

LightKeeper Pro

Fix broken string lights with the LightKeeper Pro test and repair kit. It’s easy to test bulbs, fuses and voltage to keep your holiday lights bright for years to come.