Starter Motor and Ignition Circuit Thoroughly Explained!

Learn how your vehicle's starter motor and ignition system circuit work, including how the ignition switch, relay and safety gearshift are wired to kick start the engine.
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[@fredfrancis5221]

Just fixed my wife's daily driver - our '74 Suburban - based on this video. Thanks much!

[@diypotentials]

That is amazing, great job! Thanks for sharing!

[@AlabanzasyAdoración7]

A good teacher is the one that knows how to make others to learn and understand the easiest way. You're an excellent teacher, I wish I'd had people like you around me. Most of the things I had learned is on my own with God's help figuring out how things work. Not everybody has the talent and paciente to teach others, and not everybody likes to teach others what they know that gives you a plus. Thanks for sharing your knowledge and may God give you more. God bless you!!!

[@diypotentials]

Thank you so much for your kind words. Happy new year!

[@robbonsharma6206]

He is a great instructor.Thank you so much, I was watching for understanding only but not a DIY guy.precious lesson.

[@tedbastwock3810]

I happend to already know nearly all of this, but this was still a very helpful, useful explanation to me. Thank you for making and sharing.

[@MosesSiame-ld4ud]

You are a very good teacher sir….

[@johnr.803]

Well done! I will watch this again many times to understand this complex system.

[@diypotentials]

Thank you!

[@paulmannering3831]

FANTASTIC!!! The best most complete tutorial I have seen on the starter system. Keep up the amazing work. It's inspired me to make contraptions explaining starter, injector flow testing etc!!

[@diypotentials]

Awesome! I’m glad you found it helpful. I recommend posting your projects on KZbin so we may learn from you as well…Thanks so much!

[@leahandrea3398]

~|0

[@Cooldude-tm5rs]

Just trying to learn how the different parts of my motorcycle work and this is very helpful. Thank you

[@AhmedGadd]

Thank you. Always I hear stop cranking the ignition key once the engine starts but I did not know why. Thanks for your video for explaining this point and more.

[@diypotentials]

Thanks for sharing. Happy holidays!

[@mohammadkuhinurrahman2707]

আপনাকে ধন্যবাদ এত সুন্দর করে বুঝিয়ে বলার জন্য আমাদেরকে বোঝানোর জন্য এখানে আপনাকে অনেক পরিশ্রম করতে হয়েছে

[@asmasayyad6175]

You are a good physics teacher!

[@diypotentials]

Thank you!

[@melvis2017]

Great video thanks for the good explanations. U are the man 👍

[@diypotentials]

Thank you!

[@NightWear21]

This is gold. Wow, excellent explanation. I will re-watch several times. To really hammer it in my dense skull. Above and beyond, you really know your shit. much appreciation.

[@diypotentials]

Thanks for the kind words! Much appreciated!

[@abdelaaladawi5701]

Great job bro . Very useful episodes We learn how to fix the ignition system if there is a trouble

[@diypotentials]

Thanks!

[@39bebechito]

Best ever explanation!!! Thank you.

[@diypotentials]

Thank you!!!

[@CarGalleryZa]

He put in all his effort to make us understand, great video

[@diypotentials]

Thank you!

[@patbrazil1125]

Excellent explanation, best I have seen on KZbin! Well done!

[@diypotentials]

Thank you!

[@anthonyvee]

Beautifully explained and wonderful work on the example... Thank you.

[@it5942]

Best video on this subject.

[@diypotentials]

Thank you!

[@pigeonpeaks]

Great job and helped me to understand

[@kerrybracken2903]

Very good video, thanks

[@sheriawoodard7545]

Thank you that helped a lot someone took a screws out of mine and only put one back so I feel that maybe my problem how to get that screw back up in there, to be for sure thank you again thank you again

[@sendurs7304]

Amazingly explained 👍🏻

[@diypotentials]

Thank you!

[@yokechan2765]

great teaching

[@catalinbalasic2821]

A fantastic video, with a fabulous presentation and explanation! Thanks!

[@diypotentials]

Thank you!

[@ahmedtzaki4476]

Awesome! I see this video is made for electric engineers as they understand this stuff, but I have made it out understanding almost all the ideas based on my school physics! Just one thing I didnt get: what is the main purpose of the small relay that is connected to both the safety switch (park/drive) and the contact key? You said it is for safety, but how?

[@bernardocisneros4402]

No, it's made for mechanics not engineers.

[@ahmedtzaki4476]

@bernardocisneros4402 Ok, you definitely know better as my knowledge in engineering specialties is very weak. Any answer for the question?

[@bernardocisneros4402]

@@ahmedtzaki4476 The purpose of the starter relay in this video and the vast majority of relays is to save money on wire and switching devices. A relay uses a low current circuit to control a higher current circuit. The use of relays is not due to safety reasons. It's mostly due to economic reasons. The "neutral safety switch" is used for safety so you can only start the car in park or neutral and not in drive or reverse. If you didn't use relays, you would have to use bigger and more expensive ignition switches that can handle higher currents. You also would have to use a larger quantity of thicker wire to handle the higher currents. Using the relay you can use thin wire from ignition switch to relay control circuit pin #86 and thin wire from relay control circuit #85 to ground. Using the relay also allows you to use a smaller less expensive switch. Using the relay, the only places you have to use thicker and more expensive wire is from battery positive to relay pin #30 and from relay pin #87 to starter solenoid.

[@doridturjman4822]

Great explanasion!

[@HayChhuy]

The best comprehensive. Many thanks.

[@diypotentials]

Thank you!

[@derrickellis7748]

man you're on point! Excellent tips I feel like I can do this now. thanks "...

[@diypotentials]

Thank you!

[@dylankirton1150]

Thanks for going to the trouble of showing all of that 😊😊

[@diypotentials]

Thank you!

[@nyasha8657]

Great explanation mate, keep it up!

[@diypotentials]

Thank you!

[@thompsonchidi2618]

Nice video, please how do connect a push button to replace the key starter in this procedure. Thanks

[@chaoqunhuang1516]

Very good and useful video

[@diypotentials]

Thanks!

[@mattjewett4473]

Thanks for the detail. It's going to help.

[@diypotentials]

Thank you!

[@KleoElezi-sz1rf]

Hi there I'm a new mechanic I like the way u explain the process what I don't realize is why the starter is connected with wire that comes from alternator I'm confused

[@JaredStone-q2y]

Did anyone ever answer this?

[@vtace1]

This is fantastic. Based on the fact that the positive terminal connector on the battery is connected to the positive terminal on the starter, Is it possible to disconnect the positive cable from the starter, put a load on it, and charge the battery?

[@goodghost6182]

U r stupid

[@bignick3303]

Great video thank you!

[@earthenergyhex]

wow, great instructions

[@diypotentials]

Thanks!

[@jonathananderson7329]

Beautifully explained 😤👌🏼

[@diypotentials]

Thank you!

[@jamminjamy]

Great video, thx!

[@diypotentials]

Thanks!

[@tomference4618]

Can you illustrate where an ammeter be placed in the circuit.

[@ManuelMarrujo-u2c]

thank you great video

[@birdybirdy688]

Thank you Sir! I learn a lot today.

[@diypotentials]

Glad to hear. Thank you!

[@TheHomeProjectsYeti]

Thank you a ton boss. Great video

[@shamteh88]

You're amazing hats off

[@diypotentials]

Thank you!

[@marcjwoods]

Great job!! Thanks!

[@diypotentials]

Thank you!

[@anoopc9895]

Very good explanation ❤

[@diypotentials]

Thank you!

[@GuStavo-jk1cb]

Great video. Can you do a video on internally and externally regulated alternators? How they work and are wired…older systems like for muscle cars from the 60s.

[@diypotentials]

Sounds like a very interesting video. Thanks!

[@shanek6582]

What’s the common name for that safety switch for park? Thanks man, great video.

[@diypotentials]

Gearshift, gear stick, gear lever, gear shifter? Thanks!

[@bwambaleedgar9847]

great lesson of today

[@michaelhyman3d]

Intresting didnt know it was the trigger wire that went through the safety and relay. Explains the no click sound i have. I wonder if i can jump it by passing a wire from positive to relay with the car in park. (Well maybe netrual with a brick on the clutch lever in my case)

[@bernardocisneros4402]

If you don't know exactly what your doing, I wouldn't do that. Most starting systems on today's cars are not as simple as his demonstration. They involve a lot more electronics. On most cars you can ruin an engine control module if you mistakenly jump the control side with battery positive to slot 85 and slot 85 is the ground side of the control circuit controlled by the ECM.

[@KONDWANTWAYA]

Good explanation bro

[@PristonPokam-cx8zd]

I completely understand, thanks

[@diypotentials]

Thank you!

[@ComfortOkema-ux3io]

good lesson

[@rudogwenzi4571]

Good teacher

[@leomarkmacas1497]

WOW! Very well explained!

[@diypotentials]

Thank you!

[@bakernicholas123]

thank you for this!

[@j.p9935]

Great video ! Thank you!

[@diypotentials]

Thank you!

[@WalusimbiKhan]

Great exposure thanks brother

[@diypotentials]

Thank you!

[@mabvutothewo1369]

I enjoyed this one Thanks

[@diypotentials]

Thank you!

[@josephflores9705]

the relay is mostly right, the one part is always labeled 78 and 78a on a 5 pin relay

[@HopelesslyDetermined]

Iam very thankful ❤

[@analizapablo1329]

Sir show the complete wiring diagram of starter motor to ignition switch with start relay thank you,

[@sastrawansastrawan5702]

Awesome!. thanks for your demonstration. I know it took so much effort to do this. Very much appreciated.

[@diypotentials]

Thank you!

[@ChicaneMedia]

Question, I understand that accessories will be on when the key is in ignition position but is there a way to only turn an accessory on only after the starter is on? So basically, on ignition position it won't turn on until only after the starter cranks the engine on.

[@jimmyjoel3064]

Thank you sir!

[@OthmanBonggol]

Good video bro..

[@eleanorbanwell3478]

Brilliant, thank you! Did I understand correctly, when you turn the ignition key, the entire chassis becomes part of the circuit? And the chassis is connected to the -ve terminal of the battery?

[@diypotentials]

Yes, the chassis becomes part of the circuit. Thank you!

[@charanjitsinghSeniorEEO]

What is I and R marking on DC 24V starter, Two main terminal are there for connecting+ and - from battery.

[@briantm488]

Great explanation

[@diypotentials]

Thanks!

[@diypotentials]

Thanks!

[@yakobwakjera2102]

I learned a lot

[@treztrez8660]

Thank you brother

[@diypotentials]

Thank you as well.

[@janmichaellawas776]

What size of wire you use, that thicker wire for starter motor

[@jaymausantos]

Nice video! I have a quick question. I replaced my starter on my 94 bmw 325i thinking that I have a bad starter. I checked the battery is good, starter is good, relay is good… but sometimes it won’t start. I bypass my ignition switch and used a push start. Everything works fine but sometimes it won’t start. I read online that it maybe the wire coming from my relay to the starter is bad or corroded… can I just simply put a 12 volts to the starter solenoid so when I push start the car it will start? Thanks in advance

[@diypotentials]

HeyJay, I don’t recommend doing that because solenoid is already connected to a 12volts. It might be that the ground wires are loosened or rusted…That would be something I would check next …Thanks!

[@BnisonkiHiikhanii-vi4pk]

Battery is good, what would be the problem in my car can't start even in jump start.

[@bill_de7206]

Fantastic!

[@diypotentials]

Thank you!

[@HEARTNHUSTLESTUDIOS]

Thanks!

[@DicksonMulamata]

Enjoyed the lesson

[@diypotentials]

Thanks!

[@han-eihan2145]

You are at a college instructor level, at least. Thanks.

[@diypotentials]

Thank you!

[@EnriqueGuerra-dh5pz]

Si se puede traducir en Español Soy CUBANO

[@reginaldoar-jio9413]

thank you i love you so much

[@diypotentials]

Thank you! 😊

[@JacobEwing-o1p]

Great explanation and visual!!

[@diypotentials]

Thanks!

[@philipdickson3923]

Fantastic..

[@diypotentials]

Thank you!

[@josen6546]

Excellent video, thanks. Can I ask you, looking in the relay if you don't have a good ground from battery to the relay where you have 4 cables to the relay itself you still can give power to the cable that goes to the started ? Thanks.

[@diypotentials]

The electricity has to make a complete circuit, from the positive terminal to the negative terminal. If the pathway is blocked, it will not provide electricity to the starter…Thanks!

[@ketbum]

My car pilot 2012 it has two starter relays, when I crank start the car I don’t get any voltage come out to starter solenoid. I look for starter wiring diagram but can’t find any. Any one can help me please. I tested both starter relays working but when crank start only one click the other is not

[@kingpete3160]

What happens if the battery kinda low

[@trounbyfire]

I have voltage on both wires touching starter... I don't think i should

[@mooremaceo]

Safety gear? Usually called a "Neutral Safety Switch" or "Park Position Switch". Good vid though!

[@diypotentials]

Thanks for the additional information. Best!

[@anussqadeer3181]

When I turn my key sometimes the starter motor works and sometimes doesn't

[@Sackifshi]

I know what's wrong with it ain't got no gas in it 😂

[@ZareNiksa]

Can bad starter cause no ignition power no dashboard lights no radio nothing or what else can be a problem the fuse for ignition is good

[@alberoDiSpazio]

Bad battery? My engine wouldn't crank, there was no 'clicking' associated with the solenoid but my headlights and dashboard worked.

[@kenlelon369]

my 66 chevy keeps running after you turn the key off. (?)

[@575gtcFerrari]

Damn...well good luck

[@575gtcFerrari]

If it lasts longer than 2 hours, I'd see a dr

[@David-iw6ce]

It's your ignition switch and those other comments aren't necessary the guys trying to fix his car

[@kenlelon369]

@@David-iw6ce Changed switch, prob still there but not as often. It eventually turns off, also sometimes clicks instead of starting. Always works, sooner or later

[@tmchango]

Your engine sounds like it's dieseling, I have witnessed the same issue with SBC's, it's a timing issue typically, check your valve train.

[@roumelvalero6688]

gets!

[@JesusSanchez-bw8ue]

I have a 06 gto. I thought my starter went out so I swapped it out, but got the new part in and it didn’t work. I was able to get the starter to engage by touching a socket extension onto the two terminals onto the starter, with the key on the on position the car started. When I turn the key, the starter relay clicks. Does that mean from the relay to the starter something is wrong? I’m kinda broke so I’m not able to pay someone to figure it out for me 😭

[@cowpoke6479]

yes

[@alberoDiSpazio]

Title says "Starter Motor and Ignition Circuit" but I don't see any ignition coils, breakers, distributors, or spark plugs.

[@dale_agameroftheworstgen]

He wasn't saying it as "starter, motor, and ignition circuit" like you seem to think. He was talking about a singular part of a vehicle. Lol. However, I acctually do understand how much it sucks to click on a KZbin video that seems like the thing your desperately looking for but unfortunately isn't ..... KZbin is the one to blame for that happening though, it's an interactive AI that does that to people on purpose.

[@mangetgabriel5397]

Great teaching

[@dominiomo]

Great teaching good Job I have learn from your teaching

[@KayMelaw23]

Thank you 👊🏽

[@johnbarber257]

DONT UNDERSTAND the three wires going into ignition switch ? power into ignition goes on B as in from battery. S on ignition switch goes to 30 on relay . But which terminal on ignition does wire from 86 on relay go ? You keep saying ignition but which terminal ? If the ignition has B battery S start solenoid G ground and A/L acessories / lights then is it the A/L or the G ? I am guessing A/L because G ground does not seem right to me .

[@umarmurtala5572]

Very detailed explanation. Keep it up.

[@davew6949]

Excellent teaching video!

[@diypotentials]

Thank you!

[@PeterBwalya-c9m]

Great 👍

[@Boleh888]

Thanks for the detail explanation.