How To Use a Test Light to Diagnose Electrical Problems

An automotive test light is a very handy tool to help diagnose electrical issues on many different things. A test light can help you to narrow down and pinpoint a problem on and electrical circuit on your automobile, camper, RV, boat and even a utility trailer.

This video will show you how to properly use a test light to diagnose where electrical problems may be on a circuit

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Our videos are for entertainment purposes only. It is recommended that you seek advice or help from a qualified professional while attempting any and all repairs.

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[HomeOwnerRepair]

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[mattagrella]

The only thing I would add is, after probing the circuit, seal it with electrical tape, especially if it is an outdoor harness, such as that on a trailer. The small opening could allow moisture and eventually a short in the circuit. Other than that, very informative video! Thank you!

[tmon]

Before trying on my truck I get to this video 👍
Thank you

[RampartPh]

just got an auto circuit tester and this is of great big help

[luxurycarkey]

Great video you explain it very well good job

[AlwaysDiagnoseVehicleFirst]

Could you do a video on how to read and follow the blower motor wiring diagram from start to finish, please?

[basedpatriotLT]

Why is it blinking if the turn signal is not on? I mean if you connected the bulb, it would not blink, jnless you switched the turn signal on in your car. Or is it necause this tool is connected to ground = immitates that turn signal lever is switched on?

[kelcritcarroll]

Found one of these in my dads tools….it looks old balkamp 700-1069 printed on it

[thomasoutlaw]

So you can stab through the wire like that and it'll be fine. I'm pretty sure a wire is bad or a few in my vehicle. Testing it just the first way you did I've done and the fuses. But starting to think it's the part where all of the fuse relays are. Like the actual box that holds them in their positions / proper spot is bad?? Crazy crazy chasing wiring issues

[J.Crooner]

Fantastic video wanted to know if you ever used this probe for an ATV? I have a Brute Force 750 and I was in the process of changing the spark plug. When I got ready to take the battery out it slipped out of my hand and made contact with frame of the bike before I could detach the positive and negative terminals from the battery. Now the push start button won't work. I'm just trying to determine what could of happened. All the fuses and relays are good. If you have a clue feel free to share i'd appreciate any help from anyone with intimate knowledge on the subject matter thanks.👍😎👌

[ac_tv]

Do i need to turned the key to ON position before testing or not?

[joeg]

You poke in or touch the wire to get signal ?

[BezabihBekele-bkrt]

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[nzwxrsk]

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[JasonSmith-qxzh]

H.O.R. I really can't find anything on here about making or setting up a bulb for blowing fuses to check for shortages in a line or harness? Wondering if you can show or explain how to set up one on mini fuses thanks in advance when, loose or draw.

[jjt]

Why do they make probes with a ground and only one probe? Would it not make more sense to have two probes on one end with no ground? Kind of like a light bulb with two probes coming out the bottom.
I know nothing about electronics, so sorry if that was a stupid question.

[diegocastillo]

How about on a chrysler 300 headlight not workin just got new ballist i want to know if its bulb or ballist?

[zayyarwin]

Can I use this method to determine the positive and negative of the car light bulb wiring? I need to wire the reverse camera and need to determine the polarity of the reverse light. I plan to connect the wire to the car body (as a ground) and connect the tip to each of two wires of the reverse light. I assume if it lights up, it means the wire is positive and if not, it is negative? Thanks

[davembeck]

so if you tap the 3 wires one at a TIME AND THE TEST LIGHT LIGHT LIGHTS UP THEY ARE OBVIOUSLY GOOD?

[the_polymath_guyoum]

Can i use this on a license plate light harness?