The Trainer #32: How To Read An Automotive Block Wiring Diagram

#automotivewiring #schematic #blockdiagram #wiringdiagram #electricaltroubleshooting
As we've shared with you over the years, there are three areas you need (at a minimum) to be assured of success when tackling an electrical diagnosis. The first is a solid understanding of electrical fundamentals. You need to be comfortable in your knowledge of what voltage, resistance and current are and the relationship between them. We covered those as the main topic of a Trainer video we posted back in May of this year.
Second "must have" is competence in a variety of electrical testing techniques, starting with the understanding of what your digital multimeter (DMM) can and can't do. You should know how to perform a static resistance test, static voltage test, dynamic current tests, and absolutely be confident in your ability to perform and understand a voltage drop test. We've covered these topics and more in videos and archived webinars that you'll find in the AutoPro Workshop and on our KZbin channel.
Third on the list is the ability to read and understand a wiring schematic and/or wiring diagram. These are more than just the electrical road map that tells you what components are a part of the circuit you are troubleshooting. They are also instrumental in helping you understand how the circuit works and vital to organizing your diagnostic strategy.
In the September 2013 edition of the Trainer, we'll focus on the third. We'll show you how to identify the circuit elements (source, load, control(s), circuit protection and path) and, based on that information, how to decide on what type of tests you'll need to perform. Then we'll walk you through a simple circuit diagnosis and show you how to put all this "theory" to use!
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Due to factors beyond the control of Motor Age, it cannot guarantee against unauthorized modifications of this information, or improper use of this information. Motor Age magazine (Advanstar Automotive Group) assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. Motor Age recommends safe practices when working with power tools, automotive lifts, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment seen or implied in this video. Due to factors beyond the control of Motor Age, no information contained in this video shall create any express or implied warranty or guarantee of any particular result. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained in this video is the sole responsibility of the user and not Motor Age magazine or its corporate parent, Advanstar.

[@echologged4986]

Excellent and clear video. Thank you for sharing your knowledge!

[@deshonlucious]

Thank you for your detail information, it is like going back to school to learn but this time you pay more attention because you see and understand the usefulness of the information. I really appreciate your video's.

[@labrat9296]

I am a self taught Electric golf cart mechanic, I have been working in the field for several years. Thank you for sharing your knowledge to the public, it has definitely helped me out. I owe you a cup of coffee. :)

[@tboneproductions2453]

Excellent video. If I can add one thing, when I first started to learn wiring schematics; I thought that “run” meant the vehicle had to be running. Didn’t realize that it just meant the ignition cylinder needed to be in the “run” position. I’ve gotten smarter since then, if only marginally so😊

[@travyb1401]

awesome video excellent description of how power flows and seeing how to interpret a basic schematic.

[@dermann2421]

Great Video. Thanks for sharing Your Knowledge & Passion & Energy !!!

[@MotorAgeMagazine]

You're welcome! Glad you found it helpful.

[@dariomendoza191]

AWSOME presentation and GREAt DETAIL!! thanks for sharing!!!

[@MotorAgeMagazine]

Glad to hear that Hayward! Thanks for the comment.

[@luongly8157]

Thank you for your times to make this very detailed video,

[@elriv76]

Thanks for excelent training video. I am very familiar with diagrams and electronics but really appreciate Your job. Thanks again :) .

[@letzrockitrite8469]

Thanks TRAINER .... complete/thorough/and even I understood it.

[@MotorAgeMagazine]

So I guess you liked it? :-) Thanks for the kind words!

[@jacekszczygiel2801]

Thank you for sharing your knowledge

[@MotorAgeMagazine]

Hope you found it helpful!

[@johnerway7255]

Great training and presenter.

[@JoelKSLC]

Great video and very informative, thanks for posting.

[@jamesmacneil1609]

Very good video. Thank you. Thumbs up!

[@Viper81766]

Thanks again for another excellent training video. I have started taking Engine Performance and Automotive Computer/Electronics classes and these videos are very helpful as was the Fischelli and Glassford videos. But I enjoy all of the teaching you do as well as the articles in Motor Age. God bless and thanks again.

[@68promod]

Thank you this was perfect!

[@pantelis241]

Great video Pete also always 😊 Thanks a lot 🙏

[@zzzzoheb]

So glad to found ur channel

[@willdon987]

This was helpful and iam thankful for your detailed input.

[@MotorAgeMagazine]

+Will don Glad it helped.

[@stevenmchenry9276]

Great lesson.

[@MotorAgeMagazine]

Thanks for the comment!

[@fivefortyeye540i]

Excellent electrical seminar!! As all are but this subject is weakness for me and sure for a lot of others out there..

[@davedeatherage4902]

Thank you, could you please teach additional videos on schematics? Your video today is the most I've learned on this subject of importance in diagnostics. Thank you sir.

[@isabelosaguionjr6161]

extremely helpful!

[@jeffpocius1350]

Jeff in Dryden I never comment on things, but excellent job in explaining a circuit in layman terms. I actually have a welding engineering degree, but my electrical classes from Ferris 30 tears ago weren't so clear. Thanks and I will be collecting all of your courses as I am trying to diagnose a jeep grand cherokee transmission shifting issue that is electrical not mechanical.

[@MotorAgeMagazine]

Thanks Jeff! We're glad you found it helpful. You may be interested in checking out Motor Age Training CONNECT! For a limited time, you can even get a FREE subscription to this online video training platform. Check it out at connect.motoragetraining.com

[@brandonblinkenberg5814]

Thank you so much for this video! I'm trying to troubleshoot a problem with my turn signals and I had no idea what I was looking at in the wiring diagrams. This gives me what I need to test the circuit.

[@MotorAgeMagazine]

Glad you found it helpful.

[@bignasty882]

I learn a lot watching this video

[@richardnilsen5]

#1 master teacher Excellence Thanks. 👍👍👍👍👍

[@seshachary5580]

very educative. Thank you. regards

[@davidm3210]

Great stuff, if only I were 40 yrs. younger I'm sure that I could be one of your star pupils. Thanks a bunch and here's to a happy & healthy new year!

[@MotorAgeMagazine]

Thanks, and same to you!

[@TrungNguyen-kp7pv]

Thanks , good job!

[@lightworrior4401]

Well explained sir. God bless you...and than you

[@MotorAgeMagazine]

That is correct. With the key on, power will be available on the battery side of the relay, not on the load side. Turn the relay on, the path is completed, and power is now measurable on both sides of the switch.

[@jamiuajasa2006]

Thanks for your time to explain how to read schematic wiring diagrams. More video abt the components test information please.

[@MotorAgeMagazine]

Thanks for the suggestion!

[@JUSDAR]

Very informative video even for an electrician

[@sonamyblackeskimo3618]

Thank you!

[@MichaelMcNeilg]

Thanks Pete !

[@wiringdiagrams5854]

Thanks for your information… :)

[@CHIBA280CRV]

Thanks amigo!

[@MotorAgeMagazine]

Good questions! Many modules have more than one connector. In this case, they are labeled "A", "B", "C", and "D". The letter refers to the connector, the number to the pin opening in that connector. And yes, you can find the info in Mitchell 1 OnDemand as well as ProDemand.

[@zeasman55]

I am 71 and I would like to learn more about automotive electronics I have a degree in Automotive engineering but back in 1973 so electronics were hurried through

[@muflihmansoor7755]

Great work

[@michaelsamaniego6635]

Good video 👍🏽

[@ebrahimsadeghi5883]

Great info

[@littlebeargaming8267]

Hello, Pete. Excellent video ! Could you please explain to me how the diode protects the computer and why you wouldhave a different amperage at F6 and F8 when you use and amp clamp or a dvom?

[@MotorAgeMagazine]

The diode only allows current flow in one direction. When a coil is de-energized, the magnetic field collapses and that could cause a voltage spike to try and follow the wiring back to the ECM. Without the diode, that spike would damage the ECM driver. As for the difference in amperage at F6 and F8, that's due to the different loads fed by the two. F8 powers the solenoid (very low current load) and F6 powers the compressor clutch coil (much higher current load).

[@littlebeargaming8267]

thank you so much, Sir.

[@nickayivor8432]

KNOWLEDGEABLE Sir Pete Meier Motor Age Great tutorial thank you very much for sharing it with us Sir Pete Meier Motor Age From Nick Ayivor from London England UK 🇬🇧

[@Dreccomel193]

Great video... thank you for taking the time to make it. I would like to ask why are component diagrams and OE diagrams so different? I have an electronic fan issue and I got stuck on the component diagram because it indicated that the fuse was "hot at all times" and started to check on the conjunction box for the fault. Whereas the OE diagram indicated that the fuse was "hot on run." Is it a printing issue, an oversite or just plain human error? Any thoughts?

[@MotorAgeMagazine]

I'm betting its an error on publication by the aftermarket supplier. It happens sometimes...

[@Dreccomel193]

@@MotorAgeMagazine Thank you Sir... 😊

[@tomsmith698]

Pete , First time caller looking for help. I bought a 1966 Thunderbird with electric door and wing motors. Both wing windows work . Driver window works with 12V supply, not with switch, passenger window not working with switch . have not removed passenger door panel yet. Came with new switch cluster and only three wires run from each switch. Continuity on all the wires to driver door test positive. The circuit includes a Window Regulator Safety Switch with 3 wires going to it. I don't know what this safety relay is or how to check it . Can you enlighten me. Thanks . Td

[@sashodishliev711]

I'm sorry but which program you use for this ??

[@TonyObigba-ef8we]

Please for how long is your training subscription?

[@sivucit]

hi at 17.50 you said about connector and pin..if you look at 17.50, I see 335 number, is it a connector and second depending on vin (let say vin x) I see A2, so what is a2 means, I can understand it is 2 second pin, does a has any meaning.. Also what is the connector number going to tell me, will I use that connector number to locate connector if so where is it , I don't think it is there in Mitchell, may be in pro demand to identity connector..i may be wrong.

[@boybravo689]

Thumbs up done sir new subscriver

[@jeweldawson5668]

I’m trying to learn electrical now, I’m currently a mechanic, do you really believe we can work on an all electrical car,if so we can we do to them

[@DanouTouga]

Please , i have problem how i can identify the compound easily when i find my self front a electrical shematic car thanks

[@fivefortyeye540i]

So f6 feeds e8 once switched is closed correct???

[@Buddhism4Happiness]

Great.

[@salemogla1495]

thanks a lot , do you have another video on the same subject ?

[@MotorAgeMagazine]

+salem ogla No, not specifically Maybe it's time we did another? :-)

[@MotorAgeMagazine]

If the path shorts to ground BEFORE the load, it is just like placing a wire directly across the batter posts. (DON'T try that at home!). If the short to ground occurs AFTER the load (the ground side), the load will regulate current flow just as it does normally.

[@tubetime39]

TY !!! I am seeing short to ground code (Promaster 3.6L) and AC compressor issues (forget exact wording, been a few months, but I have melting in Power Center (destroyed) ground wires at body frame near Pow Cen & headlight are burnt. Thinking short in compressor and maybe before load causing this damage. ?? Your comments here help ! Afraid to take to dealership from comments I have found. Yesterday I contacted a guy who said dealership had him come get his promaster saying they couldn't fix it ! Hoping to finally learn something about vehicle electrical after all these years. 55 yrs of doing my own basic mechanical, brakes clutches, valve jobs, tranny fluid changes etc mostly on older vehicles

[@easyuser2789]

This a great video excellent job but if you might send me the web site of the diagram sir Regards

[@redwolfmaddox3986]

helpful video

[@MotorAgeMagazine]

Thanks!

[@user-jt6ph2fs7w]

Ok

[@greg6925]

Awesome Thank You Pete

[@aba2598]

thanks

[@joeh690]

is the website free to lookup the diagrams and the symbol meanings ?

[@MotorAgeMagazine]

No, there is a small charge for access

[@mountainbiker5246]

What do the color codes mean on the wiring harness of a auto electrical system thanks for the feedback??

[@MotorAgeMagazine]

Typically there is a legend with the wiring information to decode the colors. Most are pretty straight forward...Wh-white, Bk-black, Bl-blue, etc. Two colors indicate the main color first and then the color of the stripe, or tracer, that runs the length of the wire. HTH!

[@danielvarella8861]

can anyone tell me why i no singles on left side need help

[@garyvanremortel5218]

Why wouldn't we just swap a relay out with one from a working system and cut to the chase? Relays can't easily be damaged by any other fault except a hard short in the secondary circuit. Is this considered bad practice?

[@bibektamang2505]

❤❤❤

[@sivucit]

continued.. circuit protection device.. (fuse) not sure why this should be always positive.. I mean fuse conventionally used only for positive, but you can discard and have ur negative wire and have a fuse,, I don't see any challenge in that, right?. it is just that engineers like to keep on positive side,, I can think a situation where there is good amount of resistance on positive side, but let say there is a short to power on the ground side, current will take least reistance will melt wire

[@ebrahimsadeghi5883]

Eany specific web can we get wiring diagram

[@MotorAgeMagazine]

Are you in the U.S.?

[@timbowalk]

u r the man

[@Haroon-vt6fd]

Can you tell me the best wiring , obd2 codes sensor daigram sides Like where is this sensor This sensor is here Like wiring or sensor location daigram website.

[@MotorAgeMagazine]

If you are in the States, you should be able to subscribe to any of the popular service information sites. AllData, Mitchell, MotoLogic. You can also access the OEM sites via the NASTF site at www.NASTF.org.

[@whitewolf2256]

💯

[@JesusMunoz-dw9ms]

very well done but I am afraid of frying the pcm

[@coll2006]

I'm looking for an auto electrical trainer. Can anyone recommend?

[@MotorAgeMagazine]

Are you looking for training for yourself? We have an excellent video program called Motor Age Training CONNECT you can check out for free at connect.motoragetraining.com.

[@coll2006]

Motor Age sure I'm looking for training for myself. Let me check it out thank you.

[@junherdolmo9946]

Hi, How can i get those diagrham?

[@MotorAgeMagazine]

If you're a professional, you can subscribe to a number of different aftermarket information providers. And anyone can access the OEM factory service sites - for a fee. Last, there is a product called Mitchell DIY that you can use if your a home mechanic.

[@mohammedtaha2558]

How I can find the electrical wiring diagrams for hyundai vehicles?

[@MotorAgeMagazine]

You can access Hyundai information at their OEM service information site. Here's a site that has all the OEM sites listed in one place - www.oem1stop.com

[@mohammedtaha2558]

many many thanks my Dear Motor Age for your fast reply and beneficial advise

[@MotorAgeMagazine]

mohammed taha Your welcome!

[@lyndleshelby6291]

A great explanation that would have been even better if you would have made the ultimate "problem" being a necessary sensor input to the PCM at the bottom right of the diagram. I understand that, practically speaking, you've covered the "most probable" causes, however, the presentation is weaker on the "I'm pulling my hair out" diagnostics!

[@MotorAgeMagazine]

Thanks for the comment. You may like the video I just finished for our January 2022 Trainer!

[@johnsantos7984]

THE PROBLEM RIGHT NOW MOST OF THE CAR DEALERS THEY DONT SURRENDER OR GIVE COPY OF THE WIRING DIAGRAM TO THE CAR OWNER.

[@salemogla1495]

can you help in the symbols?

[@MotorAgeMagazine]

+salem ogla Most service information systems provide a "legend" explaining the symbols used in their diagrams.

[@edgarmendez1958]

The only

[@conquistador1425]

he already checked the ground side. there is no ground at the relay!

[@danielhutchinson6604]

Adding electrical issues to Automotive problems, created a new marketplace for electronic products. The longevity of the vehicle was not enhanced. The ability to market vehicles to less educated humans, seems to have been the objective....

[@andrewjames8843]

James

[@earniesmith8754]

i ask for ranger 91 2.9 module disa what happen

[@AllanO808]

I can't see any detail on my mobile, just a few faint diagram lines.. Useless.

[@MotorAgeMagazine]

Did you try adjusting the players resolution?

[@joegood2474]

The problem with this video is not the content, it is the Title. It does not say, how to understand electrical circuits, it says how to read an automotive block wiring diagram. You spent 99% of your blabbing on the wrong subject. Thank you for wasting my time.

[@Jason-wc3fh]

This video sucks. It's for people who need to learn how electrical works and how the components work. I came here to learn how to read the diagram and I still don't know. At 1:18 I just needed to know what the W5 and X7 and C1's and other numbers represent. I don't need to be taught what a diode does and how a relay works.

[@victorsierra7633]

That is BS. I can't see nothing.