🔧 Stay powered, stay precise — the ultimate truck circuit sidekick!
The OTC 3642 Truck Electrical Circuit Tester is a lightweight, corded diagnostic tool designed for 12V-24V truck systems. Featuring a 7-inch stainless steel probe and an expandable 24-foot red coiled cord, it enables precise detection of shorts, grounds, and open circuits. Its extra-large clamp fits bigger grounding points, making it an essential, professional-grade tester for truck electrical troubleshooting.
| Brand | OTC |
| Power Source | Corded Electric |
| Style | Modern |
| Color | Red |
| Item Weight | 1 Grams |
| Item dimensions L x W x H | 13.9 x 2.1 x 0.1 inches |
| Min. Operating Voltage | 12 Volts |
| UPC | 731413505805 071090090493 012302669731 031112405643 971474694401 666661072208 012303704974 523161182243 |
| Manufacturer | OTC |
| Global Trade Identification Number | 00731413505805 |
| Model | 3642 |
| Item Weight | 0.035 ounces |
| Product Dimensions | 13.9 x 2.1 x 0.1 inches |
| Country of Origin | China |
| Item model number | 3642 |
| Is Discontinued By Manufacturer | No |
| Manufacturer Part Number | 3642 |
| OEM Part Number | 3642 |
G**S
Very well built test light
Needed a longer cord on my test light, my old one has a much shorter cord and shorter overall size. Old test light is also 12 volt. This test light is much bigger than my older test light and works perfectly for my application. I needed to reach down into a very constricted area and the added length works well for that. Ground clamp is well made and quite sturdy. Expect that this light will be trouble free for years to come.
D**.
Quality test light
Great way to add a light load so your multi meter will read loaded voltage and not lie to you. Longer wire is also nice. From back of the dump truck to the cab! Overall great product.
J**Y
Reach those hard to find places
Great having a long lead for a large vehicle. Finding a good ground on a large vehicle can be a challenge when you want to test a circuit on a large vehicle. This works well. The point on the tester is easy to work with on circuit boards and easy to puncture wire insulation to a quick test. I found I like this better than the small ones and use it to check all my DC connections and fuses. Clip is big enough to grab on to a lot of large steel or small enough to grab a small screw or wire.
D**S
Quality
Excellent tool. Very durable. Probe length is a bit long for under dash work or tight quarters, but they make different models depending on your needs. Very well built tool.
B**N
Great test light. Only one I use.
My first one of these was a Matco branded one Same exact. That one Lasted for 10 years of steady use on trailers, trucks and excavators, until it lost connection in the coiled wire somewhere. Easily my favorite test light with Plenty of length to follow wires. Worth every penny.
J**.
My favorite test light.
This is my favorite test light. I’ve used a bunch in my career as a diesel tech. This ones the best. Long cord and a clip that you can actually clip on stuff. Occasionally the bulb looses contact but allYou have to do is unscrew it and screw it back together and that will get it working again.
V**Y
A test light that won’t lie
I’m a big fan of incandescent test lights, you know, because they won’t lie to you like leds. The big plus for this one is the clamp. Love it. And the long cord is great too.
M**E
heavy duty
i like the clamp on this one. i use for bus and heavy duty trucks, many checkin bias voltage and just confriming grounds.
Trustpilot
1 month ago
4 days ago
