Thinking of buying a Powerprobe

[Hakeem]

I work as fleet mechanic for a heavy duty tow and transport shop, so I spend a lot of time dealing with simple wiring issues. These trucks all have dozens of lights, so it seems like there’s always some lighting that isn’t working, 15ft+ away from the battery.

I do ok with a DMM and a test light but I’ve kinda had my eye on a power probe. Being able to check a fixture for power/ground and then to test the component itself by applying power/ground, seems like it could really speed diagnostics up. The long jumpers + omnipresent ground would be nice, too.

On the other hand, I know that you can easily fry some of the sensitive electronics (CAN BUS, ECM, etc) by sending power in the wrong place. If I steer clear of the engine bay and stick to applying power/ground to things like lights and isolated components that I removed like blower motors, is there really much risk of damage?

Any thoughts on investing in one of these?

 

[Radio Flyer]

I also do fleet work. I have a power probe and almost never use it. Maybe once every few years. I really hate trying to get it back in the box. We tend to use a lot of after market accessories. When working in the cab, the extra power probe wire always gets tangled up. I have also seen guys get burned with it. Most commonly when doing trailer wiring. The power probe will show a ground connection, but it will not indicate how good of a ground connection it is. As long as I know I’m not working with a computer circuit, I tend to grab an old incandescent test light. DVOM for computer circuits, and an old 4652 halogen bulb as a “load pro”.

Hope this helps.

 

[mrjaw14]

Load pro would benefit you, as would incandescent test lights, and a headlight bulb for higher amperage circuits as recommended above for substitute loads. Power probes have their place, but usually not in diag work. I’d much rather understand the circuit and why it’s not working than run around applying power or ground. If you are wrong about what you’re applying power or ground to you can cause other things to operate you don’t intend. FWIW I also made myself some really long test leads for cheap. I wouldn’t let the long leads of the power probe be a factor.

 

[N8sToolz]

I agree pretty much with Radio Flyer.

I have one, rarely use it. My biggest issues is it's kind of cumbersome to pull out and setup. It only takes about 50maA to indicate power or ground. Most incandescents start around 250mA, it's possible for them to lead you astray. Same applies to LED test lights. The last thing that always bugs me is that it's been sold as the do all tool to the techs. It's not really a replacement for anything, don't get rid of your meter or test lights.

With that when I do use mine it's often for trailer lights or as a known good power ground supply to supplement a meter or test light.

If you can master voltage drop testing will put you significantly ahead with diag.

 

[signcrafter]

I use my PP3 mostly for supplying power and/or ground. For testing the actual component by supplying power and ground to it. Or getting power and ground to wherever you are working. The long cord and extension works good to get to back of truck or even a trailer. As far as circuit testing with it you can use it for a quick check but there are better tools for that. Like anything else it's just another tool in the box that is good for some things. I don't have a PP4 or hook but they have some additional features but not sure exactly what.

 

[johninct]

I could not have fixed electrical issues on my Cat 215 without a PP3.

 

[Hakeem]

Ok, good input so far. Thinking about it some more, like @signcrafter said, I’d probably just use it as a way to bring power and ground to wherever I’m working, as well as using it to test components.

Here’s kind of how I imagine id use it to diagnose a non functioning trailer light:

I’d do a quick check for the presence of power and ground. If those are both present, I’d use the PP to send power to check the light. If the light works, then I’d check the power and ground again with higher draw incandescent test light, grounding it to the power probe. In my mind, it seems like a really slick workflow … is the convenience worth $130 though? Not sure.

 

[signcrafter]

Ok, good input so far. Thinking about it some more, like @signcrafter said, I’d probably just use it as a way to bring power and ground to wherever I’m working, as well as using it to test components.

Here’s kind of how I imagine id use it to diagnose a non functioning trailer light:

I’d do a quick check for the presence of power and ground. If those are both present, I’d use the PP to send power to check the light. If the light works, then I’d check the power and ground again with higher draw incandescent test light, grounding it to the power probe. In my mind, it seems like a really slick workflow … is the convenience worth $130 though? Not sure.

Pretty much how I use it. Once your verify light is working with PP supplying power you can load test the circuit with a test light. If that fails you can load test the positive side and ground side by using test light along with PP to see which side of that circuit the failure is on. Hook test light to PP ground and trailer's positive, if it lights you know the trailer's ground is bad. If doesn't light switch leads so test light is on trailer's ground and send power to it with the PP, if it lights you know the trailer's positive side is bad. A quick and easy way to narrow it down.


I used to do a lot of installs of aftermarket car stereos and audio and other stuff like that. I used my PP a lot for that because I wasn't chasing an issue. Could assume the wiring in the vehicle was functional for the most part so you could use PP to see what was power and what was ground real quick. Yes, you could get burned if the vehicle had issues but it worked almost all the time for stuff like that. And you won't fry anything unless you get trigger happy and sending power when you shouldn't.

I also like that it has the 4mm jacks on the positive side of the PP. I cut the alligator clip off mine and put on a 4mm jack and then just keep an alligator clip with 4mm jack on the pp ground. But can pull it off and put on any of my 4mm adapters for pins or whatever.

 

[Fedwrench]

It's better to have it and not need it, than to need it and not have it. I find the long extension cable quite handy. You just need to use with a wiring diagram so, you know what circuit you might apply power to. Any tool in the wrong hands can wreak havoc. Read the powerprobe manual, watch a couple of you tube videos and it will probably save you time and make back the price of the tool quickly. I prefer the smaller versions of the powerprobe to keeps things easier to use and not bulky but, that's just me.

 

[finn]

I’ve got a couple, and find them useful timesavers, although I’m just a home user at this point in life.

I bought the PowerProbe III a couple of years ago, then last year bought the Autel version for the winter house.

In my opinion, they’re worth the money.

 

[American Locomotive]

I have a PP3. I don't use it that often, but when I need to use it, love it. As others (and yourself) mentioned, you can do some serious damage to control electronics if you start using it on computer or control circuits.

But for isolated (read: unplugged) things like lights, motors (window motors, door lock actuators, fans), solenoids, other devices that just need +12v and GND, it's so handy. The built-in voltmeter on the PP3 and up is also useful for just doing some quick voltage spot checks on active circuits, as you always have a solid ground reference, and can quickly spot "weird things". The probe is also super durable and needle-sharp, which is useful for piercing wire insulation if you need to. The long cord and extension lead is awesome for working on large vehicles and trailers. I find it packs away in the box pretty easy, even with the extension lead.

So, it is not "the" end-all of electronic diagnostics tools, but it is a useful tool if you understand its limitations and understand what can happen if you start playing with it on control circuits. I like mine, and think it's worth owning one.

The Powerprobe 4 apparently has low-current and 5v modes (which is super cool), but I've never used one and can't comment.

 

[2ndGearRubber]

I work as fleet mechanic for a heavy duty tow and transport shop, so I spend a lot of time dealing with simple wiring issues. These trucks all have dozens of lights, so it seems like there’s always some lighting that isn’t working, 15ft+ away from the battery.

I do ok with a DMM and a test light but I’ve kinda had my eye on a power probe. Being able to check a fixture for power/ground and then to test the component itself by applying power/ground, seems like it could really speed diagnostics up. The long jumpers + omnipresent ground would be nice, too.

On the other hand, I know that you can easily fry some of the sensitive electronics (CAN BUS, ECM, etc) by sending power in the wrong place. If I steer clear of the engine bay and stick to applying power/ground to things like lights and isolated components that I removed like blower motors, is there really much risk of damage?

Any thoughts on investing in one of these?

30ft retractable test leads are nice to have, cheaper than a power probe, work with your test lamp or meter. I like the magnetic ones I can clamp to the lift, non magnetic mount are ~1/2 the price. That said, they're not designed to leave a 10amp load on for an hour. The ones with banana jacks are superior otherwise you need to have gator-clips to connect to the little gators on the retractable test leads, downside is you need to solder banana jacks onto the 30ft as I've only seen banana jack models in 15ft spec.

2 Wire 30'' Retractable Test Lead Set: Amazon.com: Industrial & Scientific

2 Wire 30'' Retractable Test Lead Set: Amazon.com: Industrial & Scientific

www.amazon.com

Power probe is a nice solution for basic 12v wiring issues, I don't use mine often but it is nice when I need to do so. What you're asking for is sort of the textbook power probe function. It does not load a circuit, so you need to use it with the circuit complete or add a load like a test lamp in line for individual measurements. The nice thing with PP3 is just bypassing inputs - "will this light work if I supply power, ground, or both?". For a basic incandescent or LED tail light - you just need a good connection to the battery, and a load to substitute. PP3 is a nicer solution for sure but I don't think it's inherently faster or easier than a 9006 headlamp bulb with stacking banana jacks soldered onto the pigtail, and retractable leads. If that's the use case, the PP3 is nicer and adds more features but it won't tell you any more than that bulb and those leads.


Unplug INOP light. 9006 touching both wires, it should light. If it doesn't, 9006 on B+ of the test leads, it should light on one and not the other, ground is good. Reverse 9006 bulb to B-, it should light on the opposite wire confirming power is good. it's around a 3.5amp load on a 12v battery without the engine running.

 

[tak1313]

I'm DIY and bought one just because I'm a GJ member. Have yet to use it (at least 3 or 4 years now), but it's more because I haven't needed to yet, but it is the nice bright green one.

 

[merkyworks]

Maybe instead of a power probe take a look at blue point loadpro tester EECT180.

This vid explains how it is used and was informative for me, ff to 9:32.

 

[theoldwizard1]

What you really need,is a remote 12v source !

Buy 25' - 50' of marine 18 AWG duplex cable. Put some big alligator clips on one end and female sheathed banana jacks on the other. Connect your INCANDESCENT test light to the appropriate source and use the point of the test light to check for power or ground at the item you are testing.

Remember that a test light will limit the current to 250ma (1/4A).

 

[2ndGearRubber]

Maybe instead of a power probe take a look at blue point loadpro tester EECT180.

This vid explains how it is used and was informative for me, ff to 9:32.

Pretty sure that bluepoint tool is just a rebranded loadpro.

Electronic Specialties INC | Since 1967

Electronic Specialties, Inc. designs and manufactures quality electrical testing equipment and diagnostic tools for the automotive, small engine, HVAC and industrial fields.

www.esitest.com

 

[Wrench97]

I used mine all the time on trailer lighting, that and a mirror or two was a easy test to see if the light worked or didn't.
Pull the trailer cord out of the tractor plug and power up the light circuit on the trailer if the lights came on the trailer was good.
Words of caution you have to know the circuit you are working on do not for any reason apply power to a circuit connected to a module, sensor or other electronic component not all circuits are designed to run on 12v.
The ground clamp is very handy if only to hook your incandescent test light to.

 

[signcrafter]

Pretty sure that bluepoint tool is just a rebranded loadpro.

Electronic Specialties INC | Since 1967

Electronic Specialties, Inc. designs and manufactures quality electrical testing equipment and diagnostic tools for the automotive, small engine, HVAC and industrial fields.

www.esitest.com

It is the same thing. It's funny because Dan the inventor of the load pro had a melt down when other companies started putting a resistor in their testers to load the circuit. Pretty sure he sued snap on for doing that on a different tester they came out with. I have the load pro and his book. I like the book because it's written in a way a guy that overthinks everything like me can understand and soak up, unlike a typical text book that I can read 6 times and maybe remember the first word. Amazon has the load pro and book sold as a bundle.

 

[richfinn]

I have owned and used all these tools at some point in the past 40 years.

I think Powerprobes are perfectly OK as long as you 100% understand circuit design, but they won't diagnose every type of circuit failure (corrosion)

I think the Loadpro is perfectly fine but a little bit cumbersome in actual use.

I think incandescent Test Lights are perfectly good but without an actual voltage display can be wildly open to interpretation of bulb brightness.

You can make up a decent length of twin core cable with 4mm banana jacks at either end really cheap and use them effectively with a volt meter and a bulb to load circuits and power up components (ideal for extended vehicles/trailers).

Also consider this relatively cheap tool from Lisle, it has a Volt Meter. It can correctly identify polarity, it can apply a sensible decent load (800mA @ 12V) to test "volt drop" at the push of a button. If you replace the alligator clip with a 4mm banana jack you can use it along with your length of twin core and save a lot of time confirming if wires can actually carry current or not!!!!

https://gb.jbtools.com/lisle-28800-digital-test-light-with-load-tester/?wi=off&gad_source=1&gad_campaignid=22230753351&gclid=Cj0KCQjwnJfEBhCzARIsAIMtfKKqf_1roW8BC1n14DHaovyJoSv0RIYFfFaXVZqMlsT1yfanDhoxuoAaAnBpEALw_wcB

 

[Zewnten]

If you're so so with a DMM, a power probe won't help much. It's just a tool for speeding up the process, get/make jumpers instead.

 

[signcrafter]

If you're so so with a DMM, a power probe won't help much. It's just a tool for speeding up the process, get/make jumpers instead.

They all have their place and each is nicer for certain things. PP is nothing special but it comes in a nice easy to use package. I don't pull mine out often but for certain things it's nice and worth the investment. It's nicer to use then jumpers and multimeter for some things and comes in a nice package. Also has a built in circuit breaker which a jumper doesn't have. Everyone talks about the PP being dangerous because of it's ability to apply power but then recommends to just use jumper wires which won't have any protection unless you add an inline fuse or circuit breaker.

 

[Radio Flyer]

It is the same thing. It's funny because Dan the inventor of the load pro had a melt down when other companies started putting a resistor in their testers to load the circuit. Pretty sure he sued snap on for doing that on a different tester they came out with. I have the load pro and his book. I like the book because it's written in a way a guy that overthinks everything like me can understand and soak up, unlike a typical text book that I can read 6 times and maybe remember the first word. Amazon has the load pro and book sold as a bundle.

I like Dan’s book, but hate the font!

 

[signcrafter]

I like Dan’s book, but hate the font!

I actually like the font. Pretty sure I have some ADHD, I could never read or focus and take in information from regular text books. But for some reason the way it was written and I think the fewer words and font with carton like drawings let me take in the info in the book. Maybe it's just me.

 

[charbar]

A few years ago my Snap On guy gave me their version of a power probe to try out. I had it for a month and never even opened the box. I do quite a bit of electrical diagnostics and never found a time when I thought that tool was going to make diag any quicker or easier over my 25' set of test leads that I built for $10.

As for the 5 volt output.....how often do you really need a 5 volt power source?

 

[Kaervak]

I'm a fleet mechanic as well, nearly all the use my power probe sees is verifying if a component will function when putting power directly to it. As for wiring diag, 30ft test leads and a meter are my go to. The power probe is incredibly handy to have around, but I wouldn't make it my primary tool.

 

[American Locomotive]

A few years ago my Snap On guy gave me their version of a power probe to try out. I had it for a month and never even opened the box. I do quite a bit of electrical diagnostics and never found a time when I thought that tool was going to make diag any quicker or easier over my 25' set of test leads that I built for $10.

As for the 5 volt output.....how often do you really need a 5 volt power source?

Having a 5v current limited output would be handy for verifying sensor signal circuits. You'd use that in conjunction with a scan tool and live data.

 

[AJHD]

When I was checking lights, fuses and relays on equipment and small trailers working at the CAT dealership, I just used a multimeter and a test light. I never needed anything else to check for power and ground.

I eventually sold my PowerProbe, I never used it. We had a hand held ammo box style trailer tester which could provide power and on the equipment all I did was power on the lights.

Automotive isn't any different. It's easy to check for a bad/blown fuse, relay or bulb or if the socket is getting power. More often than not it's nothing more than a visual check.

 

[mrjaw14]

Checking for power and ground needs to be done LOADED. There is no voltage drop without current flow. Seeing 12v or continuity to ground just proves you have at least one intact strand of wire. When you load the circuit there should be only one load, the device using the power. If you have high resistance, that is a second load, and the voltage must be split between the resistors/loads, so the primary load doesn’t get all it needs. The load should drop nearly all the voltage. A DMM measures differential in voltage. So if you load the circuit and there is high resistance, the DMM would measure lower voltage at the primary load when engaged. Something like the load pro test leads makes this easy to check. remember there are only three wiring faults: Open, short, and high resistance. Power probe cannot diagnose all three, especially high resistance. If you put a DMM on a corroded wire and check resistance you won’t see it. There isn’t enough current flow out of the DMM batteries to effectively drop voltage due to the resistance. Goes back to no voltage drop without current flow.

I can’t stress enough: seeing 12v on a DMM or power probe screen does not mean you have good power. Power integrity must be verified on a loaded circuit.

for a good dose of electrical diag theory look into ohms law and Kirchhof’s laws. I’ve made good money off understanding them.

 

[charbar]

Having a 5v current limited output would be handy for verifying sensor signal circuits. You'd use that in conjunction with a scan tool and live data.

But I already have 5 volts on the vehicle I can use for free...

 

[Jweebothee]

Learn how to use it correctly, I’ve seen many techs blow an entire harness because they thought they knew what they were doing,

 

[Ole Slewfoot]

I do some fleet work as well. A year or two ago i got a gineric fake powerprobe.
For about $60, it simultaneously does some DVOM functions. Its very useful sometimes, and I'd totaly buy again If it gave me trouble which it has not. Only real negative is the storage case ***** and is too small.

It was this one. https://www.ebay.com/itm/144801866129

Probaly cost more to make nice leads that long.

 

[American Locomotive]

But I already have 5 volts on the vehicle I can use for free...

And you already have 12 volts, and ground, and...

Yes, a DMM, retractable jumper leads, test clips and piercing/back probes could do everything a Powerprobe can.

A Powerprobe is a tool of convienence. It doesn't do anything novel, but combines some basic electrical testing and diagnostics tool into one. I could get my set of leads, my DMM and then fiddle around trying to clip them onto the battery, deal with a tangle of wires everywhere ...or I just get the PP, plug it into the cigarette lighter and have one cord that goes all the way back to the trailer light I'm trying to diagnose.

 

[tak1313]

Pine Hollow has a LONG vid on the LoadPro (he doesn't like it). I never watched the whole thing because it's so long.

 

[signcrafter]

Pine Hollow has a LONG vid on the LoadPro (he doesn't like it). I never watched the whole thing because it's so long.

I haven't watched that video but he is a very smart guy. But everyone needs to recognize the PP for what it is, just another tool in the box. It doesn't do anything special and as pointed out you can do everything it can with other ways for less money. BUT, it's wrapped up in a nice package and for some things it works very good. It doesn't load the circuit so the voltage reading is just that, just like a fluke. I can hook my load pro leads up to my PP with banana jacks also if I want to load a circuit. Also can hook up a homemade test light with banana jacks. A PP is just another convenient tool that works well at certain things, not all things. It's not a replacement for a DMM or other tools. It's also no more dangerous to use then a set of test leads, if anything it's safer since it has a circuit breaker. Weather you're using test leads or the PP you have to know what you're doing and not send power to the wrong thing. I'm not a PP fan boy or anything like that. Just keep reading people saying it's junk and you can do the same thing for half the price.

 

[tak1313]

I haven't watched that video but he is a very smart guy. But everyone needs to recognize the PP for what it is, just another tool in the box. It doesn't do anything special and as pointed out you can do everything it can with other ways for less money. BUT, it's wrapped up in a nice package and for some things it works very good. It doesn't load the circuit so the voltage reading is just that, just like a fluke. I can hook my load pro leads up to my PP with banana jacks also if I want to load a circuit. Also can hook up a homemade test light with banana jacks. A PP is just another convenient tool that works well at certain things, not all things. It's not a replacement for a DMM or other tools. It's also no more dangerous to use then a set of test leads, if anything it's safer since it has a circuit breaker. Weather you're using test leads or the PP you have to know what you're doing and not send power to the wrong thing. I'm not a PP fan boy or anything like that. Just keep reading people saying it's junk and you can do the same thing for half the price.

His vid was about the LOADPRO. I THINK he likes/uses the Power Probe.

 

[signcrafter]

His vid was about the LOADPRO. I THINK he likes/uses the Power Probe.

Sorry I misread that. I'll have to watch his video and see why he doesn't like the loadpro.

 

[Brownsfan]

I really only use it now for things like checking window/door Lock motors. For quick fuse checks. Test light is fine. Loaded checks I use bulbs incandescent test light. Again used correctly. It's another tool for the box.

 

[Wrench97]

Pine Hollow has a LONG vid on the LoadPro (he doesn't like it). I never watched the whole thing because it's so long.

The load pro does not tell you anything a regular old fashion test light won't, I've seen many new guys with a dmm not understand why their 12v disappears when I put my test light in the circuit......

 

[mrjaw14]

Pine Hollow has a LONG vid on the LoadPro (he doesn't like it). I never watched the whole thing because it's so long.

I just re-watched his video. he didn't say it didn't do what it was supposed to do. What it boiled down to is that it didn't fit into his process. There are multiple ways to arrive at an answer. What's important is to find a tool that aligns with your preference and level of diagnostic knowledge. If you aren't comfortable with ohms law or Kirchhoff's laws you need something that aligns with your knowledge to use, but there's super super smart guys that just use test lights most of the time, but they know how to apply it properly and what they are telling them.

What I appreciated about PHAD's approach is that he articulated the electrical theory and was smart and learned enough to understand the limitations of the loadpro. things like intermittent fault requiring more amperage to reproduce, like a relay that fails when heat-soaked or duty cycle controlled circuits may require a different approach. His other concern was the size, but if you aren't getting a loadpro in you aren't getting a power probe in either.

At the end of the day each issue requires a choice of what tool to use, and you may not use the same one each time. LoadPro and Power Probe don't do the same things. They are different tools and require different methodologies to use. If your thought process makes more sense to use one or the other, more power to you. I advocate knowing why you are choosing what you are chosing. It can be really easy to mess things up with a power probe. LoadPro not so much. I find a lot of people don't know how to properly use a power probe, but also don't understand what a loadpro is telling them. Whatever you use, take some time to understand why things are doing what they are doing and some basic theory behind it.

 

[signcrafter]

The load pro does not tell you anything a regular old fashion test light won't, I've seen many new guys with a dmm not understand why their 12v disappears when I put my test light in the circuit......

I learned this lesson the hard way a long time ago, freaken corrosion kicked my *** but taught me a valuable lesson.