Automotive Circuit Tester Pen With LCD Voltage Readout, Continuity, Resistance and Diode Check, Smart Test Light for Fuses, Relays, Switches and Wiring
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If you don't love it, return it within 31 days. No questions, no stocking fees.
A Test Light That Tells You The Number, Not Just That The Bulb Lit.
A plain test light answers one question: is there power here or not. This pen answers the next three. The LCD shows the voltage at the probe tip, so you can see a weak 9 V feed instead of a healthy 12 V one, and it checks continuity, resistance and diodes so you can prove a fuse, a relay, a switch or a stretch of wiring good or bad without dragging out the multimeter and a handful of jumper leads.
What It Is, And What It Is Not
It is a smart test light: a probe with a meter readout for the checks that make up most electrical diagnosis on a car, which are power, ground, continuity and voltage drop. It is not a full multimeter, and it is not a power probe. If you need to feed power or ground to a component to make it run on the bench, that is a power probe, a different tool; our circuit tester versus power probe video walks through which one you actually need.
One safety note that applies to every test light: stay out of airbag circuits and module connectors with a probe. Use a multimeter on those. Everything else on the car, lights, horns, windows, blower, fuel pump, grounds and fuses, is exactly what this was made for.
How To Use It
- Clip the lead to a known good ground, the battery negative post or a clean bolt on the engine or body.
- Touch the probe tip to the point you are testing and read the voltage on the LCD. Battery voltage means power is present; a reading several volts low means resistance somewhere upstream; zero means an open circuit, a blown fuse or a switch that is off.
- Check a fuse without pulling it by touching the two small test points on top. Both at battery voltage, the fuse is good. One at voltage and one at zero, it is blown.
- To check a ground, move the clip to the battery positive post and probe the ground wire or ground point. Battery voltage on the screen means the ground is good.
- With the power off, use the continuity and resistance functions to prove a wire end to end, a switch open and closed, a relay coil, or a diode.
- Unclip when you are done. Keep the probe tip off anything you did not mean to touch while it is connected.
Watch: Diagnosing Car Electrical Problems With A Test Light
Our mechanic shows where to clip, how to check fuses, relays, power wires, grounds and switched circuits, and which systems to leave to a multimeter.
What It Finds
Everyday jobs
- ✅ Blown fuses, found from the top of the fuse box without pulling each one.
- ✅ Dead outlets, lights, horns, blowers and window motors: power at the connector or not, in one touch.
- ✅ Bad grounds, the cause behind half of the strange electrical complaints on older cars.
- ✅ Voltage drop across a corroded connector or a tired relay, which a plain test light cannot show you.
Why a pen instead of a meter
- ✅ One hand free. Clip once, then probe; no second lead to hold on a ground.
- ✅ Readable in the dark, under a dash or in an engine bay at night.
- ✅ Fits in a shirt pocket or the door pocket of the shop truck.
- ✅ Built in protection against shorting the probe, for the tester and the car's electronics.
From An Owner
"Smart test light. Super handy! Better than a test light and much easier than grabbing jumper wires, alligator clips etc. Great addition to electrical supplies."
Specifications
| Tool | Pen style automotive circuit tester with LCD readout and clip lead |
| Reads | DC voltage at the probe tip on the LCD |
| Checks | Continuity, resistance and diodes; fuses, relays, switches, connectors and wiring |
| Vehicles | Cars, trucks, SUVs, motorcycles, RVs and boats with 12 V electrical systems |
| Protection | Built in safeguards against short circuit damage to the tester and the vehicle's electronics |
| Not for | Airbag circuits and control module connectors (use a multimeter); household AC |
| In the box | Circuit tester pen with lead, user manual |
| Weight | About 1.2 lb shipped |
| Returns | 31 day returns, US based support from Towson, Maryland |
Frequently Asked Questions
Is this better than a regular test light?
For diagnosis, yes. A bulb lights at 9 V and at 12.6 V and looks about the same. This shows you the number, which is how you catch a corroded connector or a weak ground before you replace a part that was fine.
Does it replace a multimeter?
For most work under the hood and under the dash, it will be the tool you reach for. Keep a multimeter for airbag and module circuits, for current measurements, and for anything where you need a lab grade number.
Can it power a component, like a power probe?
That is not what it is for. It reads and checks circuits. A power probe sends power or ground down the probe to run a fan, a pump or a window motor on demand, and that is a separate tool.
Will it damage my car's computer?
It is built with protection against shorting the probe, and a digital tester draws far less from a circuit than an old incandescent test lamp. Still, keep the probe out of airbag connectors and module pins; that rule applies to every test light ever made.
Does it work on 24 V trucks?
We sell it for 12 V vehicles. If you need it for a 24 V system, email us before you order and we will check the rating for you.
What if it is not what I expected?
Send it back within 31 days for a refund. Email support@youcanic.com or call 1-888-959-4265 with your order number.
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