Specs are compiled from manufacturer listings and verified buyer reviews and can change over time — please confirm the key details on the product page before buying.
Your tree is half dark and the whole string is still tangled around the branches. You do not need to buy a new set — you need the right little tool to find the dead bulb. The picks below split into two jobs: a tester that locates the break, and a repair gun that fixes the shunt inside a dead bulb without swapping it.
This guide is built by comparing the manufacturers’ published specifications and the patterns across verified customer reviews, so you get each pick’s real strengths and trade-offs instead of marketing spin.
Most dead strands trace to a single failed bulb or fuse, so one tester pays for itself the first time a section goes dark. I break down each pick below so you can choose the xmas light repair tool that actually matches your set.
Top Picks
How To Choose The Best Xmas Light Repair Tool
Start with your bulb type, because that one decision rules out half the shelf. A tool built for traditional incandescent strings will not fix an LED set, and an LED tool will not touch incandescent. Check a bulb before you buy anything.
Incandescent or LED — check before you buy
Incandescent bulbs have glass and get warm when lit. LEDs usually have a plastic cap and stay cool. A tool like the LightKeeper Pro is built for incandescent series-wired sets, while the LED Keeper is built for LED series-wired sets. Buy for the lights you actually own.
Series-wired versus parallel-wired strings
Pull one bulb from a lit section. If that whole section goes dark, your set is series-wired and a repair tool can help. If the rest stays lit, it is parallel-wired and most of these tools cannot assist — check before you spend.
Do you want to find the fault or fix the bulb?
A voltage tester locates the break so you can swap the right bulb. A trigger-style repair gun fixes the shunt fault inside a dead bulb, often without a swap. Some kits bundle a tester, a fuse checker and a bulb remover so you cover both jobs.
Side-by-Side Comparison
| Model | Best For | Light Type | Detection Range | Spare Fuses/Bulbs | Amazon |
|---|---|---|---|---|---|
| BOJACK Fuse Kit★ Best Overall | Restocking fuses for the whole season | Fuses, not bulbs | — | 100 fuses, 6 rated types | Amazon |
| ALLOSUN Non Contact TesterBest for Finding Faults | Locating a break in incandescent strings | Incandescent | 12–600V AC | None | Amazon |
| ALLOSUN Tester + Fuse CheckerMost Adjustable | One-hand screening with stepless sensitivity | Incandescent | 12–600V AC | None | Amazon |
| allsun GK13 Kit + 50 Bulbs | Fixing a tree in one session | Incandescent | 12–600V AC | 50 bulbs, 2.5V / 0.17A | Amazon |
| allsun GK13 + Battery Tester | Year-round kit with battery checks | Incandescent | 12–600V AC | 50 bulbs, 2.5V | Amazon |
| LightKeeper Pro (Single) | Shunt-trigger fixes in seconds | Incandescent | 120V | 10 clear bulbs, 2.5V / 170mA | Amazon |
| LED Keeper | Repairing series-wired LED sets | LED | 120V | PODs included | Amazon |
| HLS TEST-200 | Gun-style testing with an audible detector | Incandescent mini lights | — | 5 spare bulbs | Amazon |
| LightKeeper Pro Bundle | Full incandescent kit with 50 bonus bulbs | Incandescent | 120V | 50 clear bulbs, 2.5V / 170mA | Amazon |
Detailed Reviews
1. BOJACK Christmas Light Fuses Kit
Our pick — 4.5+★ from 750+ verified ratings; the strongest balance of quality and price.
A 100-fuse assortment in a plastic case, so a blown fuse never ends the night.
Half of dead-light calls are a blown fuse, not a bulb, and this kit solves that problem for the long haul. You get 100 fuses packed in a plastic storage case, split across two physical sizes and six current ratings. The 3.6x10mm fuses come in 2.5A, 3A and 5A, and the larger 5x20mm fuses come in 4A, 5A and 8A. Every fuse is rated at 125 volts.
The glass body, the through-hole mount and the 2.88-ounce case weight all point to one thing: this is a refill, not a tester. It has no voltage pen and no bulb remover, so pair it with one of the testers further down and you cover the two most common failures. The selection is what carries it — this is the widest fuse spread on the list.
The honest catch is reliability — a small share of owners get fuses that do not blow cleanly or fit snugly. For most people the assortment holds fine, and 100 pieces means running out is not a worry for several seasons. It runs 4.5+ stars across 750+ owners, the highest score in this group.
What earns the top spot
- 100 fuses across six rated types — 2.5A/3A/5A in 3.6x10mm and 4A/5A/8A in 5x20mm
- 125V rating matches standard holiday light sets
- Glass body with through-hole mount for a clean fit
- Storage case keeps spares sorted, not scattered
- Lighter than most full tools at 2.88 ounces
Where it falls short
- No tester or bulb remover — a fuse kit only
- A small number of buyers report fuses that did not work properly
- Will not fix a dead bulb, the other half of most failures
Reach for this if: you have a working tester already and just need a deep stack of spare fuses on hand.
Look elsewhere if: your set is dark because of a bulb — this kit cannot test or replace one.
2. ALLOSUN Christmas Tree Light Tester
Trace the wire, catch the dead stretch, pull the bulb — all from one handheld tool.
You run the tip along the wire without touching a conductor, and it flags where voltage stops. The detection range is 12V to 600V AC, which covers household strings and outlet checks alike. It runs on two 1.5V button cells, and the box includes the batteries plus a manual. The built-in bulb remover pulls stubborn bulbs out of the socket, and a switch on the tester powers it down to save the cells.
The accuracy is the part owners lean on most — it finds the live stretch of a strand reliably. That said, the tester only works on incandescent strings; it is not built for LED sets, and the manufacturer says so plainly. Every bulb has to come out to be tested individually, so this is a locate-and-replace tool, not a one-shot fixer.
The fit note is honest and worth knowing: some owners find it works beautifully on their set and others find it does not work for every string type. It is a 3.5+ star tool across 300+ buyers, so set expectations around incandescent use. Slip it in a pocket and work the strand top to bottom.
What it does well: traces live and dead sections across 12–600V AC, with a built-in remover to pop bulbs after you find the fault.
Know before you buy: incandescent only, and each bulb has to be removed to test — LED owners should look at the LED Keeper instead.
Fits best: the homeowner with older incandescent strands who wants to hunt down a break fast.
Think twice if: your trees are LED — this tester will not help there.
3. ALLOSUN Christmas Light Tester
A scroll wheel instead of fixed clicks — dial the sensitivity until the dead spot gives itself up.
This is the only tester here with stepless sensitivity. Instead of a few preset levels, you roll a wheel to tune detection smoothly until it reads the wire. Detection runs 12V to 600V AC without contact, and at the lowest setting it can tell a live wire from a neutral in a 220V socket. A red LED flashes and a buzzer sounds when voltage is present, and the pace of both rises with the signal strength.
On top of the pen you get a breakpoint locator, a bulb test, a fuse check, and a retractable bulb remover at the tip — slide the switch forward to extend it. The whole thing runs on two 1.5V LR44 button cells. There is a pocket clip on the back to keep it on your person while you work a ladder.
The catch is a real one: this is incandescent only, and a handful of buyers found theirs did not work at all. Test yours on a known-live outlet the day it arrives.
Why it stands out: the scroll-wheel sensitivity adjustment lets you tune precisely, which fixed-click pens cannot do.
The trade-off: a short track record and no LED support — verify it works before the season starts.
Best suited to: someone who likes fine control and works incandescent strings on ladders and rooflines.
Skip if: you want a long-proven tool or your display is all LED.
4. allsun GK13 Christmas Light Repair Kit
The GK13 tester plus 50 incandescent 2.5V bulbs in five colors — incandescent sets only.
Where the tester picks above only find the fault, this kit gives you the spare bulbs to finish the job. It bundles the GK13 tester with 50 replacement incandescent bulbs in five colors — red, purple, blue, pink and green. Each bulb is rated 2.5V, 0.17A and 0.43W. It comes with the 1.5V LR44 cells installed. The tester itself combines a non-contact voltage detector, a bulb test, a fuse check and a built-in remover, all in one body.
Owners who keep it in that incandescent lane find it easy to use. What it cannot do is work with LED, and the maker says so up front. Pair it with the BOJACK fuse kit and you cover fuses and bulbs from one case.
The mixed reports on this kit come from people who expected it to work on newer sets. It is a 3.5+ star kit across a couple hundred buyers, so it earns its keep on traditional sets. That said, the maker notes you should check base fit before pressing a bulb home — a loose amp rating can waste a bulb.
Why this kit earns a look
- 50 spare bulbs in five colors for same-night repairs
- 2.5V, 0.17A and 0.43W rating matches standard incandescent strings
- One-part kit: detector, bulb test, fuse check and remover
- LR44 button cells included, ready to run
What to expect
- Incandescent only — no support for LED sets
- Some owners mention the tester did not work at all
- Each bulb must be tested individually, so it is not fast
Pick it when: you own incandescent trees and want tester plus spares in one box.
Pass if: your lights are LED — check the LED Keeper instead.
5. allsun GK13 Holiday Light Repair Kit
A bulb-and-fuse tester plus a BT20 battery checker that stays useful after the tree comes down.
Three tools in one box: a non-contact voltage detector from 12V to 600V AC, a bulb and fuse tester, and a separate BT20 battery tester. That last part is the difference. Plug in AA, AAA, C, D, 9V or a 1.5V button cell and it reads the charge — useful year-round, not just in December. The gun-style body is shaped for one-handed use, and it carries 50 2.5V incandescent bulbs in red, purple, blue, pink and green, each rated 0.17A and 0.43W.
Alerts are both sound and light — a beep and an LED — so you get a clear signal on a dark strand. It runs on two 1.5V LR44 button cells, and you slide the switch back to power down to save the cells. Like its sibling, it is built for incandescent strings and the maker warns it may not work with every LED string.
The honest fit note is that some owners find the bulb-and-fuse tester hit or miss on particular sets. The battery tester is the dependable half of the kit.
Read the value: you get a bulb-and-fuse tester plus a separate battery checker that keeps the kit useful after the season ends.
Watch to keep it short: use the battery tester briefly — longer test times drain the battery under test.
Grab it for: a home that fixes both holiday lights and household batteries from one kit.
Look on if: your lights are LED or you want a long-proven tester.
6. Quick Fix Incandescent Christmas Holiday Light Set Repair Tool
Squeeze the trigger and it pulses the strand to reset the shunt inside a failed bulb.
The LightKeeper Pro carries UL Listing #230566 and is rated for 120V household circuits, which is what your strings plug into. Instead of chasing a break, it fixes the most common fault directly. Most series-wired sets die from a shunt issue — the tiny wire inside a bulb that is meant to keep the rest lit fails open. Squeeze the trigger and the tool pulses the set to reset it. For everything else, an audible voltage detector finds the interruption in the circuit.
Included in the 4.8-ounce body: a bulb tester, a fuse tester, a bulb puller, a storage compartment for spare bulbs and fuses, and 10 clear replacement bulbs rated 2.5V and 170mA. The 1.5V alkaline batteries come installed. The manufacturer lists a lifetime warranty that excludes the batteries and bulbs.
Here is what it will not do: it is not for LEDs, rope lights or sets with control boxes. If a bulb has already blackened, it has no life left and the tool cannot revive it. This is the tool the crowd trusts — 4.0+ stars across 10,000+ ratings — and it finally beats the fiddly testers by fixing the cause in seconds.
Why it wins seasons: the Quick Fix trigger clears a shunt in seconds, and the set keeps lit — no bulb chasing.
What it cannot do: blackened bulbs, LED sets, rope lights and control-box sets are outside its range.
Buy it if: your tree is incandescent, series-wired and half dark right now.
Not for you if: your display is LED or runs on a control box.
7. LED Keeper Complete LED Christmas Holiday Light Set Repair Tool
The only LED-specific pick here — PODs bridge a bad socket so you do not need the exact replacement bulb.
LED trees are their own repair problem, and this is the pick that targets them. The LED Keeper fixes series-wired LED sets by swapping in a POD at the faulty location. It comes with 2 replacement PODs plus 4 extra green ones, and universal PODs that assist with socket issues or when you cannot find the exact replacement bulb. You get a bulb and fuse tester, a bulb puller, a 9V battery and 2 place markers to keep your spot on the strand.
The part the reviews keep coming back to is speed. Finding the problem takes minutes, and each POD swap is quick. LED sets wired in parallel are outside its range — the maker says many pre-lit LED trees are parallel-wired, and the Keeper cannot assist those. It also does not touch incandescent sets.
It weighs 15.68 ounces and carries a lifetime warranty from Ulta-Lit that excludes the batteries and bulbs. It runs 4.0+ stars across a couple hundred owners. One test tells you if your tree is compatible: pull a bulb from a lit section, and if the section goes dark, you are series-wired and this tool fits.
Where the LED Keeper delivers
- Built for LED series-wired sets that most testers cannot touch
- 2 replacement PODs plus 4 bonus green ones, plus universal PODs for socket issues
- Bulb and fuse tester, bulb puller and 9V battery in the kit
- Lifetime warranty from Ulta-Lit, excluding batteries and bulbs
Clear limits up front
- Will not work on parallel-wired LED trees
- Does not work on incandescent sets at all
- Heavier than the handheld testers at 15.68 ounces
Suits you best: the LED display owner whose pre-lit tree is series-wired and half out.
Think twice if: your LED tree is parallel-wired — this tool cannot help.
8. Christmas Mini Light Tester and Repair Gun – HLS TEST-200
A pistol-grip tester for mini-light strings, with five spare bulbs stored in the handle.
The HLS TEST-200 is a pistol-grip tester with an audible voltage detector and storage built into the handle. Five spare bulbs come with it, so a quick swap is always within reach. The big 10 x 8-inch footprint makes it easy to find in a garage, and it runs on battery power so you are not tied to a cord while working the strand.
What people tend to like is the overall satisfaction — the tool does the job it sets out to do on mini light strings. That said, a number of buyers found theirs did not work at all, and opinions on ease of use are divided. It is a 4.0+ star tool across 200+ buyers, so it works for most, with a small tail of duds.
The gun shape is the reason to consider it: the grip, the spare-bulb storage and the audible detector all make it a fit for someone who wants to hear the fault, not just see it. If you prefer a slim pen you can pocket, the ALLOSUN picks are a tighter carry.
The appeal: gun-grip comfort with an audible detector and five spare bulbs stored in the handle.
The caveat: a short tail of units that arrive dead — test it before the season.
Right for you if: you work mini-light strings and want a comfortable grip with spares in hand.
Skip if: you want a pocketable pen-style tester or need LED support.
9. Lightkeeper Pro Incandescent Christmas Holiday Light set Repair Tool
The single LightKeeper’s Quick Fix trigger and voltage detector, plus 50 clear 2.5V bulbs and a battery tester.
Same Quick Fix trigger and the same audible voltage detector as the single tool, but this bundle loads you up for a full season of repairs. You get 50 clear 2.5V, 170mA bonus bulbs and a battery tester on top of the gun. The whole kit is UL Listed under #230566, and the battery tester is the add-on that keeps it useful after Christmas. It runs on battery power — the maker cuts the cord so you can reach the tree away from an outlet.
Weighing 7.04 ounces, it is heavier than the single tool, but the extra bulbs and the tester justify the bulk. The maker’s quick fix handles the shunt fault in seconds, and the audible detector takes over for the rest.
The limits are the same as the single version: it is not intended for LEDs, rope lights or sets with control boxes, and a bulb that has already blackened cannot be saved. It runs 4.0+ stars across 800+ owners, so this bundle earns its place at the top of the incandescent shelf. The 50 bonus bulbs push it past the single tool for anyone starting a season from scratch.
What the bundle adds: 50 clear 2.5V, 170mA bulbs and a battery tester, matching the single tool plus a full season of spares.
What stays the same: incandescent-only, and blackened bulbs are beyond its help.
Choose this: an incandescent household wanting a season’s worth of spares and the fix built in.
Not for you if: your lights are LED or run on control boxes.
Know the Specs
Voltage detection range (12V–600V AC)
A non-contact tester flags voltage without touching a conductor. The range on these pens covers household strings and outlet checks, so you can confirm a wire is live or dead before you work it. Bring the tip close and it beeps or lights up when voltage is present.
Shunt and series wiring
In a series-wired set, bulbs rely on each other to stay lit. One dead bulb makes the whole section go dark. The shunt inside a bulb is a tiny wire meant to keep the rest running; when it fails, a trigger tool can reset it. Pull one bulb to test which wiring you have.
Bulb ratings (2.5V, 0.17A, 0.43W)
Spare incandescent bulbs carry a voltage, current and wattage rating. Match the rating to your string or the bulb will not light properly. The GK13 kits and the LightKeeper bundles list 2.5V bulbs at 0.17A and 0.43W, or 170mA for the LightKeeper clear bulbs.
Fuse sizes and amp ratings
Holiday light fuses come in physical sizes such as 3.6x10mm and 5x20mm, each with amp ratings. Match the size and amps to the set. A 125V rating is standard for these fuses. Keep a range of ratings on hand so a blown fuse never ends the night.
Common Questions
Will the LightKeeper Pro work on my LED Christmas lights?
How do I know if my lights are series-wired or parallel-wired?
What is a shunt issue on incandescent lights?
Do these testers work without touching the wire?
Can I test each bulb on the string, or do I have to pull it?
What fuse sizes are in the BOJACK fuse kit?
Will a blackened bulb light again with a repair tool?
Does the battery tester in the allsun kit check household batteries?
What batteries do the tester pens run on?
Do these tools have a warranty?
The Bottom Line
For most homes the winning pick is the BOJACK Fuse Kit, because a blown fuse is one of the two most common reasons a strand goes dark and 100 fuses cover you for seasons. If you need to find the fault fast, grab the ALLOSUN Non Contact Tester for its 12–600V AC detection and built-in bulb remover. And for a full seasonal repair kit on an incandescent display, the LightKeeper Pro Bundle is the one to reach for.
Whatever you pick, match it to your bulb type first — incandescent or LED — and check for series wiring before you buy. That one check saves more wasted evenings than any single feature.
How we choose
We do not accept paid placement. Every pick is matched to a real buyer and a real use-case; we do not hands-on test units.
Sources
Specifications: manufacturer listings and product documentation. Review insights: verified customer reviews, as of November 2026. Pricing: not shown on this page (it changes often); check the current price via the retailer link.
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