Test Light vs Circuit Tester: Which One Should You Buy?
Test light vs circuit tester: one digital test light and two circuit testers compared on load checks, voltage range, probes and cords, with a verdict and Shop Scores.
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Top picks at a glance
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- 1
V200 Pro Automotive Circuit Tester9.7/10View on Amazon - 2
ANCEL PB100 Automotive Circuit Tester9.7/10View on Amazon - 3
AWBLIN Automotive Test Light 3-60V DC Digital LED Circuit9.7/10View on Amazon - 4
3-72V DC Automotive Test lightView on Amazon - 5
Test Light AutomotiveView on Amazon - 6
Heavy Duty Automotive Test Light Circuit TesterView on Amazon - 7
Automotive Test Light with 3-48V LED Digital ReadoutView on Amazon - 8
Automotive Test Light with 3-120V LED Digital Voltage DisplayView on Amazon - 9
OTC 3642 Truck Electrical Circuit TesterView on Amazon
Verdict: Choose the test light side if you want the Lisle’s load-applied check for an instant voltage drop reading. Choose a circuit tester if you want a simple power indicator: the OTC listing also claims to locate shorts, grounds and open circuits, and the CRAFTSMAN covers 6, 12 and 24 volt systems.
A dead circuit in the dash and a trailer plug with no power ask for different tools. This test light vs circuit tester comparison puts one digital test light against two circuit testers, using the three listings as concrete examples, then scores each one.
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Lisle 28800 Digital Test Light with Load Tester
The Lisle 28800 is a digital test light with a load tester that can apply a load to get an instant voltage drop reading. The listing states a 48 in cord with a heavy-duty alligator clamp, 12 by 4.5 by 2 in dimensions, model 28800, an ETL specification met and a limited lifetime warranty. Not for use on airbags.
Pros
- Applies a load for instant voltage drop readings
- Heavy-duty alligator clamp on a 48 in cord
- ETL specification met
- Limited lifetime warranty stated
Cons
- Voltage range not stated on the listing
- Not for use on airbags
- 48 in cord is shorter than the 12 ft OTC cord
- Probe type not described in the listing
CRAFTSMAN Circuit Tester, 24V (CMMT14103)
The CRAFTSMAN CMMT14103 is a circuit tester for 6, 12 and 24 volt systems. The listing states a red LED that illuminates when a connection is made, a heat and oil resistant coiled cord extending over 10 ft, a sharp probe for piercing wires, 1.6 ounces weight and 12.83 by 4.84 by 1.38 in dimensions.
Pros
- Covers 6, 12 and 24 volt systems
- Red LED illuminates on connection
- Heat and oil resistant cord over 10 ft
- Sharp probe for piercing wires
Cons
- No certification stated on the listing
- No warranty stated on the listing
- Single LED gives less detail than a load tester
- Sharp probe needs care around wire insulation
OTC 3633 Mini-Coil Cord Circuit Tester , Red
The OTC 3633 is a mini-coil cord circuit tester for 6 volt and 12 volt systems. The listing states a needlepoint stainless steel probe for back probing and piercing, a threaded probe with a screw-on alligator clip, a bright red high-intensity replaceable bulb, a 12 ft red heavy-duty coiled cord and 2.85 by 8.55 by 1.7 in dimensions. Model 3633 with a one year limited warranty.
Pros
- Locates shorts, grounds and open circuits
- Needlepoint probe for back probing and piercing
- 12 ft heavy-duty coiled cord
- Replaceable high-intensity bulb
Cons
- 6 and 12 volt only, no 24 volt stated
- No certification stated on the listing
- Item weight listed as 1 g in the spec table
- Slim handle may be hard to grip with gloves
More options to compare
3-72V DC Automotive Test lightCheck price on Amazon
Test Light AutomotiveCheck price on Amazon
Heavy Duty Automotive Test Light Circuit TesterCheck price on Amazon
Automotive Test Light with 3-48V LED Digital ReadoutCheck price on Amazon
Automotive Test Light with 3-120V LED Digital Voltage DisplayCheck price on Amazon
OTC 3642 Truck Electrical Circuit TesterCheck price on Amazon
Side by side: test light vs circuit tester
| Test light (Lisle 28800) | Circuit tester (OTC 3633) | Circuit tester (CRAFTSMAN CMMT14103) | |
|---|---|---|---|
| What it does | Applies a load for voltage drop readings | Lights up to show power; locates shorts, grounds and open circuits | Lights up to show power |
| Voltage range stated | Not stated | 6 and 12 volt | 6, 12 and 24 volt |
| Probe | Heavy-duty alligator clamp on a 48 in cord | Needlepoint stainless probe with screw-on alligator clip | Sharp probe for piercing wires |
| Cord | 48 in cord | 12 ft coiled cord | Over 10 ft coiled cord |
| Indicator | Digital with load tester | Replaceable high-intensity bulb | Red LED |
| Certifications stated | ETL | None stated | None stated |
| Warranty stated | Limited lifetime | One year limited | None stated |
Example figures are manufacturer rated, as published on each listing and collected 22 October 2026.
What each side does
The test light side is represented by the Lisle 28800, a digital test light with a load tester that can apply a load to get an instant voltage drop reading. The circuit tester side is represented by the OTC 3633 and the CRAFTSMAN CMMT14103: the OTC listing calls its tool the standard in electrical system troubleshooting, with the capability to locate shorts, grounds and open circuits, while the CRAFTSMAN listing describes a red LED light that illuminates when a connection is made. The load feature belongs to the Lisle example alone; the circuit testers light up to show power, with fault locating claimed by the OTC listing only.
Voltage range and probes
The OTC circuit tester states use with 6 volt and 12 volt systems, with a needlepoint stainless steel probe for back probing and piercing plus a threaded probe with a screw-on alligator clip. The CRAFTSMAN circuit tester states suitability for 6, 12 and 24 volt systems, with a sharp probe for piercing wires and a heat and oil resistant coiled cord extending over 10 ft. The Lisle test light states no voltage range; it uses a 48 in cord with a heavy-duty alligator clamp.
Cords, indicators and limits
The Lisle test light is a digital unit with a load-test function, a 48 in cord and a heavy-duty alligator clamp. The OTC circuit tester uses a 12 ft red heavy-duty coiled cord with a bright red high-intensity replaceable bulb in a slim clear handle. The CRAFTSMAN uses a heat and oil resistant coiled cord over 10 ft with a red LED. One hard limit is stated: the Lisle listing says not for use on airbags. Neither circuit tester listing states an airbag warning, which is a reason to check the manual, not a win for either side.
On certifications and warranties, the two sides split cleanly. The Lisle test light states an ETL specification met and a limited lifetime warranty. The OTC circuit tester states a one year limited warranty and no certification. The CRAFTSMAN circuit tester states neither. A stated certification and warranty term are checkable facts; their absence is not a defect, but it leaves those two criteria unscored.
Example testers
For more choices, see the best automotive test light under $15, and the test light vs multimeter comparison if you need actual voltage numbers.
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Frequently Asked Questions
What does a test light with a load tester do?
The Lisle 28800 listing states it can apply a load to get an instant voltage drop reading. The OTC and CRAFTSMAN listings describe indicator lights that show when a connection is made; the OTC additionally claims to locate shorts, grounds and open circuits. Only the Lisle listing mentions a load feature.
Can I use a test light on airbags?
No. The Lisle listing states not for use on airbags. Applying a load or probing airbag circuits can deploy them; use the correct diagnostic procedure for supplemental restraint systems.
What voltage systems do these cover?
The OTC circuit tester states 6 volt and 12 volt systems. The CRAFTSMAN circuit tester states 6, 12 and 24 volt systems. The Lisle test light states no voltage range, so check its manual before use on a given system.
How do you find a short with a circuit tester?
The OTC listing states its tester locates shorts, grounds and open circuits, with a needlepoint stainless steel probe for back probing and piercing and a screw-on alligator clip for versatility. The listing includes an instructions guide; follow it rather than improvising a procedure.
Do I need a digital test light or a basic circuit tester?
It depends on the job. The Lisle digital test light applies a load for voltage drop readings, which suits diagnosing weak circuits. The OTC and CRAFTSMAN circuit testers light up to show power, which suits quick checks; fault locating is claimed by the OTC listing only. Neither replaces a multimeter where you need exact numbers; see our analog vs digital multimeter comparison.
Related: the best automotive test light for beginners, best automotive multimeter for troubleshooting and the diagnostics and electrical hub.
