Diagnosis and Understanding- Voltage Drop

Even most advanced DIY's and troubleshooters are not familiar with Voltage Drop Testing. This video shows a real life example of how lack of knowledge of this important skill can lead to misdiagnosis!
Further, voltage drop is illustrated in an easy to follow manner so you will understand voltage drop for the rest of your life without having to look up how to do the testing or when it might apply.

Other videos with voltage drop test or relevant material:

[qwe]

I have been an electrician for 40 yrs, a US navy trained aircraft electronic tech for 4 yrs and have taught the subject as an NCCER certified instructor. I have never thought about testing for voltage drop very much under load. My hat off to you young man. You can always learn new things. Excellent video

[hanyemara]

Been a diesel mechanic for 6 years first time to understand that continuity and resistance test aren’t good enough to decide that the circuit is good or bad. And you will never know that you have a hole in the water hose and the hose is bad until you apply water to it and same goes for wiring. You’re freaking awesome thanks a ton

[moog]

The best tool in anyone's toolbox is the brain. It doesn't cost a penny to upgrade it, just a little time and help from other people. Thanks Mat.

[labradormcgraw]

This guy never ceases to amaze. He has a true gift for enlightenment. This video is actually a great complement to a much more recent series: 'Basic Electrical for Beginners'.

[director]

Excellent explanation of 'voltage drop'....You showed the hands-on, as well as the theory under different scenarios....This is what proper teaching and learning is all presentation is done perfectly, and allows us to grasp the details of what some of us thought we knew over the years...Keep up the good work.

[jpattoncook]

I’ve sat through years of college courses, math, chemistry, physics, etc. Your teaching is as good as ANY college professor, any professional seminar or instruction that I have ever had. Thank you.

[allorobiekwe]

I was on the verge of changing my starter motor before I saw this video. I had the same problem and it's fixed now. Thanks so much for your very helpful video.

[electronmarkboggess]

I was a mechanic in the Army for 12 years and that's the one thing all the troubleshooting procedures I've ever followed didn't have you do was voltage drop testing.They would instead have you "ohm out the wire" to look for resistance lol..They sent a bunch of us to an advance electrical course at a local collage and that's where I was introduced to voltage drop testing and many other very good procedures that our training and manuals didn't teach..
great video!!

[WOODOGS]

I have studied electrical concepts and theory for twenty years.  Your video is the best explanation, image, and approach to this mysterious subject that I have always wondered about.  Obviously, you have wisdom about your craft, and I appreciate you sharing that with YouTube.  Thank you again for your time.

[PineHollowAutoDiagnostics]

Great video, Matt! Another great application of voltage-drop testing that I discovered yesterday: locating breaks (opens) in your rear window defogger grid!
Instead of poking around with an ohmmeter, just turn the defogger on, clip the ground lead to the ground cable on the grid, and use the positive lead to probe each line in the grid in the middle of the window. If you read 6V (~half of B+), then that line is carrying current OK. If the reading is B+, there is no current on that line, and the break is DOWNSTREAM of the + lead. If the reading is close to 0V, then the break is UPSTREAM. It literally took seconds to locate three separate breaks using the voltage drop test, after 15 minutes of frustration with the ohmmeter :)

[thomvogan]

You are by far the best teacher on the internet. I live on a small pension so anytime I can fix something myself it's a big help. I've been having intermittent problems with dim or no headlights along with slow wipers. Thanks to this I now know I probably have a bad wire or connection on a circuit that controls both. I see this video is dated 2015, hope you're still putting them out. Thank you

[Curtiss]

This is awesome. As a diy'er-wannabe, I learned more in 33 mins from this guy than several hours of watching other videoes.
Well done sir!

[labradormcgraw]

This guy is brilliant! Just can't understand why he hasn't got more subs. He makes things so easy to understand - the hallmark of a great teacher. Love the format; love the visuals; love the commentary. This guy knows how it's really done.

[anthonycruz]

This is by far the best explanation that I've seen mad respect for this man that took the time to make this video

[staind]

I appreciate your time you took to make this video. It really helped me understand how to diagnose and measure voltage drop.

[web]

Damn. 33 minutes!!!? Maybe the best 33 minute youtube video I've seen in a long time. I've spent 2 days doing exactly what you did, replacing starter, relay, nuetral safety switch, checking ignition switch, wailing and knashing of teeth.

[davidperrone]

Dude, very very good video. Way better than a lot of the other videos I've watched on YouTube. Thank you.

[raycook]

This is the best electrical video I have seen. It makes you aware to explore all avenues before a part replacement. It makes me think differently now.

[patriciacollado]

this guy is a professor!! 5 stars from me. thank you boss!!!

[yusufronco]

I'm really glad that channels like this exist. Being able to work on your own vehicle is very freeing and stress relieving, knowing that your life isn't at the mercy of under-built/ disposable modern cars.