The Trainer #29: Understanding How Electrical CIrcuits Work and How to Test Them

#voltagedrop #automotiveelectricaltroubleshooting #electricaldiagnosis #multimeter #voltmeter
The car in your bay isn't talking, and providing you with few clues as to what ails it. The schematics laid out on your workbench may as well be the undecipherable ramblings of a toddler for all the sense they make to you. The flow chart you're using says something about measuring 5.0 volts on pin "A" of the sensor connector but you're not sure why it should be 5.0 volts and not the 12.5 volts you measured at the battery. You remember something that instructor said at the electrical training class you attended a few months back about something called "voltage drop". Would that explain why you're reading the 5.0 volts on your meter?
You go back to the car and hook up for the next test the trouble tree is instructing you to do. You don't know why you're taking this test. And it isn't the easiest connector in the world to get to. Maybe you can skip this one and move on to the next? For that matter, why don't we just skip to the bottom and "replace with a known good component" to see what happens?
Your frustration is building. You've been at this for most of the day and still don't see the light at the end of the tunnel.
Then you look across the shop at Bob. Bob thinks he's just the greatest tech who ever lived. He loves doing electrical work, says it's clean work and requires very little heavy lifting. And, as much as you hate to admit it, he's pretty good at it. You're betting he'd have this car fixed by now if he'd had pulled the ticket before you.
There are three areas you need to know you know before you'll be as comfortable tackling electrical problems as Bob seems to be. First, you need to understand some basic electrical theory. Second, you need to understand how to read an electrical schematic. And third, you need to understand the voltage drop testing technique. In the May 2013 edition of the Trainer, we'll focus on strengthening your electrical fundamentals foundation so you'll have a solid base to build on. And we guarantee that if you study the basics enough to make them automatic in your thinking, you may even be better than Bob when tackling electrical gremlins in the future. Click this link to subscribe to Motor Age! bit.ly/MA_YT_freesub

[@heyitschinoable]

Im studying for my A6 ASE this has helped me more than my study guide. Because it gives me a visual representation instead of just words in a book. Thank you for making these!

[@MotorAgeMagazine]

Glad you found it helpful!

[@m33p0n3]

That's what I get for not watching until the end! Coming from a hobbyist electronics background, vehicle electrical seems pretty simple to me. But I always appreciate all the material you guys put out there, and there's always that little nugget of knowledge that'll save the day sometime.

[@rolandos64]

Hands down the best video to date I have seen about automotive electricity 101. I’ve seen many of your other videos, those of others and nothing sums it up so clearly and simple to understand. I watch videos daily, relentlessly to try to learn how to and concepts about automotive electricity. I’m also a bit certain I can do troubleshooting myself, but w out access to diagrams, that’s my next downfall. My next weakness I’m working on is lab scopes. Doing my best to learn how to use them, interpret them and set and read the waves. This video is awesome. Should be the first video anyone watches interested in automotive electricity Thank you!!!!

[@MotorAgeMagazine]

I believe that's one of the video links we added to the end as additional resources for anyone who wanted to learn more! Thanks for the comment!

[@MotorAgeMagazine]

Hey, glad you're finding them helpful. Thanks for taking the time to leave a comment!

[@juangallegos4250]

I like you video you look very professional and the information that you provide,Tank you.

[@m33p0n3]

Nice primer on electrical systems. This would tie in really well with the voltage drop seminar you posted a couple months ago.

[@max-ng8rc]

Great channel and helpful videos!

[@MotorAgeMagazine]

Thank you! Be sure to share with your friends!

[@vlovewbus]

Your awesome! Love your videos! You make things so much simpler than most people, you actually know what your talking about.

[@MotorAgeMagazine]

Thanks Shaun! Glad you're finding them helpful.

[@nickayivor8432]

Good Afternoon Pete Meier motor age Great tutorial thanks👍 From Nick Ayivor from London England UK 🇬🇧

[@paradoxdea]

I like the Donkey reference...lol!!

[@vin605]

Will explain video excellent !

[@greenball9]

Good video,,,thanks

[@luckymutibo9848]

Am learning alot

[@angelitot3113]

Thank you!

[@khurramali007]

sir we love your videos.

[@MotorAgeMagazine]

Thanks!

[@jah12010]

thank you

[@stevenmchenry9276]

Wow

[@JPNZBOXER]

Hi I'm trying to find the voltage drop link you're speaking about. Can you send me the link.? Thanks

[@MotorAgeMagazine]

This is an older video, but we've added a lot on electrical since. Go to our channel page and search "voltage drop"...you'll find plenty!

[@JPNZBOXER]

Thanks for taking time to reply. I love your videos. And find them informative. I'm doing my auto electrical trade now. (3rd trade after light vehicle & heavy plant and machinery qualifications.) these videos help solidify my electrical knowledge. Many thanks

[@billwilliams6338]

MOTOR AGE, Can you make a youtube video using the oscilloscope on spark plug waveforms look like. I have seen voltage and current fuel injector waveform or i haven't seen what spark plug waveforms look like on an oscilloscope. The Distributor cap is what sets the firing order? why do cars use different firing orders any advantages in use different firing orders? Older 60's & 70's cars only used ONE ignition coil to fire 8 spark plugs, but the fuel injectors need multiple ignition coils per spark plug, any reasons why?

[@MotorAgeMagazine]

Hi Bill! Sure, I can make a note to add that to my growing list of topics to cover - gladly! On to your next question. No, the distributor cap does not set the firing order. That is the engineers' job. And for the last - using one coil to fire all of the spark plugs is not as efficient as using one coil per cylinder.

[@billwilliams6338]

@@MotorAgeMagazine thanks, can you please make a video explaining dwell time because i don't know what dwell time is or what it does to the RPM and how to look and measure for dwell time on the oscilloscope waveforms

[@curtpiazza1688]

👍

[@anthonysova7117]

I’m confused. Substances which have few free electrons are poor CONDUCTORS it’s not the number of electrons it’s the free electron in the valance shell yes or no?

[@MotorAgeMagazine]

Materials with few electrons in the outer ring make the best conductors because they are easier to break free. Those with more than 3-5, if I recall correctly, are better insulators because it's harder to break them free.

[@anthonysova7117]

Yes sir have a nice 4th

[@nealk6387]

Look up Dan Sullivan on KZbin. He's tought me a lot.

[@Ensource]

thanks!