How to Diagnose and Find a Short Circuit or Wire in Your Car

In this video I am going to show you how anyone can easily diagnose and find a short circuit or wire in their car. You more than likely have a short circuit if a fuse in your junction box keeps blowing, it is more likely a positive or power short to a negative or ground side of a circuit.
Here are links to products which were used in this video:
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Test Lead Set with Alligator Clips: amzn.to/2mTLGdz
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Disclaimer:
Due to factors beyond the control of Ratchets and Wrenches, it cannot guarantee against unauthorized modifications of this information, or improper use of this information. Ratchets and Wrenches assumes no liability for any property or personal damage that may arise from doing a repair on your vehicle after watching any of my repair video's. Due to factors beyond the control of Ratchets and Wrenches, no information contained in this video shall create any express or implied warranty or guarantee of any particular result. Again Any injury, damage or loss that may result from improper use of tools, equipment, or the information contained in this video is the sole responsibility of the user and not Ratchets and Wrenches.

[@thejackofalltrades5171]

Millions of videos on KZbin about this. Been frantically watching many and end up confused as f$&k. This one was clear, to the point and made a hell of a lot of sense. Good job sir!

[@DavidJackson-zc4eq]

Learned more here in ten mins than a whole lifetime of reading text books, electricity always goes the easiest route when under load, been scratching my head as to why i was getting volts but the circuit wouldn't work, now I know, thank you so much!

[@gaitamaemmanuel]

Am from Tanzania...mzee we ni hatari nakuelewa sana..whenever i enter into your class i never came out empty...🙌👍👍

[@Bcr3106]

This is the video i've been looking for. You obviously understand how electronics work versus some of the car guys who don't understand and just show how to do parasitic draw tests. Hopefully I can find my short now!

[@kiarnastoon6475]

I realised after I purchased my BA XR6 about 5 months ago that it had been....electrically r@ped. Excuse the phrase but there is literally no other way to describe the disgusting state of the wiring harness. Modifications had come and gone as people had purchased and sold the vehicle over time and 'easiest route possible' appears to have been taken with the install of EVERYTHING ...EVER. I have permanent scarring (lol) on my back from being upside down (Head in footwell, feet on headrest) followiing wires trying to decipher WHAT THE ACTUAL f people have done. My DTCs were changing daily...hourly even.. Now that 99 percent of the insanity has been repaired I only had 1 fault left to tackle and that was one I couldnt work out, a short to ground but wasnt blowing any fuses. After watching this video I now realise whats going on, its happening BEFORE the fusebox. Thank sweet baby Jesus for your great vid, you have saved me a great deal of time (which an auto electrician would have too, but I like doing things myself). Sub added, cheers.

[@doyouknowpeter1954]

i used to be frightened of the seeming complexeties of auto electrics but now i take it on as personal challenge to know all i can. you are a huge help and even an inspiration. thankyou.

[@samymabrouk4196]

I been on the floor as a Mechnaic for a long time and I tell you, you have something, I was missing and that is, good knowledge and concept for electrical systems, thanks for your help

[@wardw1234]

Excellent video! I loved the simple electrical whiteboard drawings and your very clear and detailed explanations. Thank you!

[@scottc3165]

This was very helpful. Thank you. I have shorts all over my daily drivers and am beginning to tackle them one by one.

[@carlwallace3372]

Great video! Thank you for taking the time out of your day to do this tutorial. The cutaways to the white board and the comments/further explanation re: resistance in the circuits, as well as sharing what you have found to be the most common types of shorts, etc., was really helpful!

[@rone1523]

Yes, a great video but one thing you have wrong in your diagram. The switch is always on the positive side of the circuit not the negative and the fuse is always on the positive side other wise if there is a short it would burn up the positive wire/cable. The exception is a door jamb switch or some similar switch but that switch is just suppling the ground to complete the circuit in those cases. The fuse is usually located close to where the positive wire connects to the junction box/terminal/battery positive. The order of location in a circuit is 1-battery positive/ 2-fuse/ 3-switch/ 4-load circuit such as light bulb, motor, heat element, electronics, ect. This way you are always protecting everything downstream of the fuse in case of a short.

[@hanlercastillo2807]

It can’t be better explained as you did it, thank you for teaching

[@tudocervera3764]

very well explained..thank you so much for helping out us garage mechanics..

[@domingohernandez4189]

you do a great job explaining things to me..... keep up the good work, your awesome!!!!!👍😎

[@angelacosta4567]

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[@QuocNguyen-hu9vl]

I appreciated the way you show how to test a short circuit on continuity. But the approach seems for people already knew and experience what you have learned. If someone never test, experience and gain the knowledge that you does, that would be a challenge for them.

[@BellaRocko]

You're an excellent mechanic/technician/teacher! And yes, it IS all clear now, thanks to you! Thank you for educating me and many others!

[@nigelcharlton-wright1747]

Love the little drawing of the car in the wiring diagram, it looks like a '60's/'70's Hillman Hunter. Now I will have to check the wiring on my old car.

[@jonrogers558]

I really appreciate your vid I forgot some of my diagnostic lessons and you reminded me of a lot thanks again!!! I'm Definitely a subscriber!

[@wyattoneable]

Your very good at explaining things. The editing is flawless and I love the white board of knowledge. I'm good at mechanics but circuits still challenge me, this helps a lot buddy!

[@waen606]

Great demo 's and info ..thank you ..

[@josephsfields]

I thought your pronunciation of "AC-compressor" was iconic until I heard you say "continuity". Enjoy your videos and whiteboard lessons. Keep up the good.

[@inFALable]

You are a great instructor! Thanks

[@BruceLyeg]

Good explanation. Thanks for the video.

[@Komuniecki]

Great simple video! thank you!

[@247PHI]

You sound really knowledgeable and I'm having a tough time getting someone to understand what my car is doing. It's making a hissing sound in the dash like wires are shorting out but nothing is really happening to my electronics. Except that the Bluetooth part of blutooth/Satellite enabled radio hasn't always worked since i for it 7 yrs ago, but this is first I'm hearing very faint, but constant sounds like wires are touching and shorting out in my dash on driver's side. 😮

[@MasterChief-sl9ro]

Always make sure the right size fuse is in there as well. I had a lady go through 2 condenser fans on a dodge. Someone had a put a 15 amp where a 30 amp went. So as the fan hit high. It blew the fuse.

[@mortonsfarm652]

Thank you so much for making this video, all the others I found described parasitic draw. I believe I have a short to ground.

[@lsedanolg]

Yeah it seems i have one for my abs

[@ases5004]

Very informative and hoping it will help me diagnose no interior lights on my Accord after changing all fuses. Thank you

[@numerouno2532]

Very rarely do I see videos that explain so well and in such detail. This is a great video, keep it up. Thanks

[@jarradhirschausen3553]

Pp

[@chucklewis8640]

Very helpful video. One suggestion is to show exactly what pins on the headlamp connectors or headlight switch you are testing. In my case the taillights and the cluster light are out and there is one fuse that keeps blowing every time I turn on the headlights (low beam).

[@meganjay30]

That's exactly what I need to check on my car..... Got an O2 sensor problem and been trying to fix it for like over a year now..

[@vihreelinja4743]

HAving issues with p038 my self. had any success?

[@jamest6391]

Awesome teaching!

[@roadworthy6901]

Love the series, thanks!

[@myRatchets]

np, glad to hear. cheers

[@joetorres7052]

excelent video!

[@richmeister1175]

Thank you so much! GREAT VIDEO!!!!!!

[@heroknaderi]

Thanks for thid video very informative.

[@abelvasquez7165]

Good video having issue with my Chevy silverado with a short on my starter!

[@mikepettengill2706]

nice and clear, thanks

[@ja.935g67]

Got to love your sarcasm 😂

[@myRatchets]

Glad to hear, stay tuned for more.

[@aaronmcdonald4944]

Thank you so much. I'll try this on my 2006 Scion TC tomorrow. My AM1 (Ignition/CIG/ACC) fuse keeps blowing and I'm trying to figure out why.

[@chatchatty2155]

very werll exsplained can you shed any light on why i have front lights on seat codoba but no back or fog lights coming on also do you no is the a relay fitted to light cercuit thanks

[@reynaldoclaveria100]

excellent explanation valuable video.

[@lanceshroades6309]

I love your videos. You always show really helpful information. Please don’t use (or write) bad words. I really like my young boys to watch you stuff. Thanks

[@DangerousFreedom88]

As soon as one man seeks authority over another man, they have rejected freedom and it's very essence.

[@ThompsonBMXbikes]

Nice vid dude.

[@GOMEZJ76]

great video and very informative like always

[@myRatchets]

Glad you like the video, thanks for commenting.

[@gunnarjensen5910]

I had a small fire in the wires when the wiper/washer unit caught fire... I changed it but am wondering if these two problems are separete or connected ? The old wiper/washer unit only worked in one mode (max speed) The replacement works in all modes, slow, fast, int...The old one might have been dameged before it burned completely, un-insulated wire(s)..?

[@timochoa1]

Great video!!! I am helping my dad find a short in his 61 Chevy car. It does not really contain any negative wires to any of the things like tail lights interior lights or dashlights. Which are all out. (Since it keeps blowing a fuse). It simply uses the body of the vehicle as the ground. I can't find any breaks in any of the wires. Is it best to start checking each wire with one end on the body of the vehicle and the other end of the multimeter at the end light bulb wire? And repeat this for every light that is out? And make sure there is no Continuity, correct?

[@Willywallass]

Great video. My issue is my airbag clock spring keeps shorting out. I’ve replaced it twice in the past year and it just shorted out again. No fuses are blown, but I know it’s bad because I have the exact same symptoms as before. Once I replace it they all go away until it stops working again? Any ideas on how to troubleshoot this would be greatly appreciated 🙏 Thank you

[@theodoreholland7781]

You r good at teaching sir.

[@Ogrodii]

Great teacher well explained you know your stuff Thanks !

[@TheMrFlyBoy18]

Going to do some diagnosing as to why my 15amp fuse keep blowng for my 2004 Nissan Xterra. Odometer lights, p,R,D lights are out and the same goes for the lights for the ac, fan speed and the direction of where the air travels to. Front, front and to your feet, etc. this helps narrow down my search. Will start doing this sometime this week

[@mikeneal12]

@5:24 "You're f****d" 😆🤣ROFL 😆🤣 I didn't see that one coming. Thanks for the excellent video!

[@defmud80]

How would I test a sensor connector to see if it has a break in the wire or a short? Its a 3 wire connector that goes to a input speed sensor to a transmission (2002 hyundai elantra AT)

[@arturojimenez4382]

I added 4 LED strips to my truck and most of my dashboard lights went out. I tapped into the positive and negative cables for the power outlet & I used 2 displacement connectors one for + and one - .. could this have caused a shortage on my wires bc I checked all the fuses n they are all good, none of them are blown out.. and if I undo everything I did, will everything work find?

[@paulepling]

I'm wondering what's the best fuse to pull and test connector in the ECU box for 02 sensor faulty trouble codes, and if I could damage the box shaped fuses by pulling on them wrong. How do you check a gray box fuse, since they're not like other fuses u can see if they're blown

[@D-TECH886]

thanks fraind for this good information

[@gilbertreyna534]

Thanks good stuff!

[@RanGer-498]

question I have a short that keeps blowing the fuse to my ODBII port in a 2005 Pontiac vibe ...if I change the fuse it will be OK for a few days (2-3) then the fuse will pop again, I do notice when this happens because the check engine light will turn on I found out it was the ODBII port when I tried to connect the odb2 diagnostic tool and realize it wasn't working...any help I'm stumped. ..thxs

[@michaelbaskinmichael9862]

I have no turn signals or emergency flashers, was testing using a test light hooked it to flasher hot to do blue wire on turn signals. When this hooked up it starts to blink with test light hooked up. Why is that what's it saying it might need? Maybe ground or short to ground idk. Thanks enjoy your videos

[@rogeryanez8107]

Nice video brother, Quick question will a bad bulb socket cause the fuse to blow? Thanks ✌

[@josephr1868]

Hello sir my mom has a 08 malibu 3rd brake light and reverse light work sometimes but mostly not what do i look for or do?

[@gunnarjensen5910]

One wire from my cars (1986 Ford Econoliner 350XXL) headlight switch seemt to constantly overheat when the high beam is turned on... And after about 15 minutes the lights shut off... Can you advice.. I discovered one red wire was torn, and the relay made noises until I connected the wires and changed the fuse.. But still the high beam wire becomes super hot when using the high beam ??

[@Raj-cf6fe]

When I tested the continuity of the park bulb socket, multi meter beeps when connected. Is that normal? I get my abs light on dash as soon as I switch the park and tail light on.

[@yenzokilo455]

watching this in hopes to fix my car radio! a month or two ago my radio unit randomly stopped working. So i checked my fuse box and found my right side front headlight fuse is blown, upon trying to replace the fuse it immediately blew again. But my right headlight works just fine? Not sure how this is effecting the radio but damn i wish i knew someone like you in my city who could figure it out :/

[@treycee9444]

Hay how r u i have a 2006 Cadillac dts I try to start and it keeps blowing the transaxle ignition fuse I'm confused could you help

[@johnnyjohn8073]

The magnetic field you described as "ghost" voltage when wires in close proximities in the same harness become active from multiple components getting activated is a good mental visual for positive shorts.

[@smilerdon]

Every thing he's saying makes sence ,my issue is with my reverse light,I changed the bulb and still not working ,so I checked the fuse chamged the fuse and it blew straight away ,I did that 3 times , so where would I start checking

[@rightandleftish]

After re-connecting the negative wire to my car's battery there was a large spark and now I have a no crank no start situation. I thought I must've shorted the fuel pump relays (my car has 2) or the MFI relay because the pump doesn't' prime after reconnecting the battery and turning the key, but after bench testing all 3, they seem to be working just fine. Would the next thing to check be the wires going directly into the fuel pump? Any help would be appreciated - I am so lost and frustrated

[@tylerkimdura6690]

I used to have a red 2007 Saturn ion coupe! I miss that cat sooo much. Had over 250K miles

[@Joshg1984]

Great cars. i have a 2004 with 204k miles.

[@lalogarcia7172]

Hi I have a question. I have a 95 gmc jimmy 4.3l v6 with a vortec engine. I have been having some issues with rough idol. It also has been backfiring from in the Throttlebody . As well as from the exhaust an it’s been hesitant while accelerating an at driving seeds. I replaced the distributor cap and rotor as well as camshaft position sensor. Plugs an Warriors as well as ignition coil. I also replaced the crankshaft position sensor. In doing so I noticed. That the wire harness was old an wires had been arcane do to bare wires touching together. So I cut old wires an connecter an replaced it with new one. After doing that now my truck just turns over but doesn’t start. Also I to a look at my Fuses an the fuse to the ECM was blown. Replaced it with new one. An truck still won’t start. It ran before I replaced the wire harness an crankshaft position sensor. But now no start. If you help please. Thank you

[@TuthHurts911411]

Anyone know if a o2 sensor 4 wire having heater and sensor grounds swap would cause issue CEL light heating circuit low?

[@andrameda1]

Hello Rachet n wrenches, I have a Toyota corolla 2000, it is a no crank in park and crank in neutral not start in either park and neutral. The starter relay load side terminal lights up test light; control side does not light up test light however with meter a 3.44 voltage reading was discovered Key in ON position is this a short to power or ground side? When key in start the voltage is 12 .39 volts, on the control side of relay neutral safety switch is good shift selector good too, when in reverse or drive no voltage reading. Throttles sensor voltage is 1.30 volts open/close throttle no change; is the ecm seeing the low volt reference 3.44 on control side will not crank starter in park because it is not pulled down to oo ground, is it a shorted throttle sensor? Up date on voltage drop test battery positive to battery cable on starter with key in ON position remote switch pressed it dropped to 0.50 volts from 12.40 volts from battery. Negative battery to negative solenoid terminal key in ON position starter turning engine over slowly ground voltage drop 8.04 volts. Is this starter dead shot need a new starter? Peace, AL

[@nickayivor8432]

KNOWLEDGEABLE Ratchets and Wrench 👍 for sharing it Take care and have a great day KNOWLEDGEABLE Ratchets and Wrench From Nick Ayivor from London England UK 🇬🇧

[@jonnylopez159]

What if you have a fuse blown that has peace of coper wire on it does it effect the car in anyway

[@iammarauder5418]

If my lights flicker does it mean theres a short? My brake light and headlight on the left intermittently flickers.

[@7amood.alharthi]

Dear i have toyota land crousir 2004 4.7l and i have short in fuse ... when i replace the fuse direct short come again and its effect to window and ac control also fog light and release gear from P position i cannot release use the brack it shoud user manual release bottom near gear .???? What should i do ???

[@johangray344]

Hi for some reason my car does not want to start i drove it and then parked it and when i wanted to drive it again it did not start i found out that my fuel pump relay is not activating at all only when i open it and the press on the metal plate it the actives , also my injectors arent spraying fuel when you take them out and you test them they do spray what could this be?

[@CarlosGarcia-tq6do]

Thank you 👍🏻👍🏻👍🏻👍🏻

[@laserfalcon]

I have a flasher fuse instantly blow soon as you turn on turn signals, where would you start?

[@mllobetc]

Can you explain how to diagnose a short to signal wire with a multimeter and not a test light? How to get round this ghost measurement you mention?

[@danetted-r1525]

We have a 07 rondo and of late the back brake kept blowing the fuse, then the cyclops light stopped working and the mechanic just disconnected the cyclops light altogether so i could drive it. Now the rear windshield wiper stopped working, next the front windshield wiper defroster stopped working, the interior light does not come on, and just recently the rear defroster button started clicking when i turn it on do i quickly turn it off again as I’m afraid every fuse is going to blow. Its snow season here soon so wondering if you have any insight what may be causing all this. Also is the fuses near the driver door connected/different from relay under the hood. Thanks!

[@sidowsidow]

please do video on Power Circuit Probe Kit how it works and how to use short diag ... thank you!!!!!!!!!

[@BourneThisWay]

So I had an interesting problem happen recently. I installed a new AC unit in my car and not even a day later, the circuit board in the AC unit had a hole burnt into it. I checked my AC fuses and relay and neither of them were blown. Does that mean that a problem occurred before the fuse box and relay box closest to the battery? The AC was also off when it happened.

[@jessicariffle2097]

My 2006 explorer keeps blowing a fuse and burning up coil packs also. Have replaced 3 times. Guessing it's a ground somewhere. How do I find it if that's what it is. Need someone's help to put me in right direction

[@Aurora22586]

I have a turbo actuator that I am getting fault codes that it is shorted to positive. I assume the last time the engine came out to do the timing chain, some of the wires got damaged. That or the actuator itself is faulty: what is the best way to find out what is at fault in this scenario?

[@stevemcgowan3017]

Fuse blew again on siren when replaced after clicked alarm fob but siren still works ?

[@aakudev]

Exactly happened to my civic. Accidently had a short and now the igps oil fuse doesnt have power. Didnt blow the fuse and check engine light is on. How to check where is the short?

[@chankokhoi4496]

Tqvm Brother

[@joelmenard8176]

So I checked the plug with multimeter. Plug has 3 slots. OL on both the green and red slots. The black slot shows a low reading? What does this mean. My fans can't coming on in the car. When giving direct power to the fans one works and one doesn't? They both have fan control modules. Wire harness is 3 slot power to fan from fan control is 2 slot?

[@jaykross8794]

thank you

[@Bashi-Bupe]

I am using Nissan xtrail model 2001 .. Its browsing fuses and now my cars park lights and reverse lights are not functional

[@abdslil1054]

Thanks for your tuto i've Audi C6 won't crank, starter will engage if i jump wired and start the engine normally, but will not engage with its relay i replaced 4X relays but all the same, vcds says 50 short to ground, also 50 short to plus,?? i disconnected 50(+) that going to starter solenoid and short is gone, if i replace wire, short will back. So starter it self has continuing 50(+) to its body(-), is that normal?? if not i tested three 3X Audi used starter and has same continuing 50(+) to body(-), i got NUTS, PLEASE HELP...thanks in advance

[@sher12346weng]

Hello can you please help me. Recently i replace my o2 sensor because have check engine light and the code is p0141 so i replace it after a few minutes of driving engine light comes on again the error code is p0138 which is again in the o2 sensor. Whats is problem with that? Im hopping you can give me some ideas to diagnose it properly

[@kidmystery2010]

I got a 2007 trailblazer thats blowing the acc and the lighter fuse but only when my wife's oxygen machine is plugged in. There are two separate fuses for these circuits. It only blows which ever its plugged into either acc or lighter. We ran the machine for months no problem at All now it blows the fuses. Phone chargers don't blow the fuses. We exchanged the machine for a new one still blows fuses. Im at a loss for what it could be. I've changed the sockets still blows em.

[@ciprianionutapetroaie7314]

One, I have a problem, I changed the wheel hub and rear abs sensor of my car and I have two light bulbs on the abs and ESP traction control board, and I found when I put the tester on my car it gave open circuit/short circuit to b+, right? what would this mean, what could it be

[@Cateran72]

I had a new radio put in, and all works well until I turn on headlights to vehicle... that's when my fuse to my stereo blows. Please tell me where to look and how to find the culprit

[@badgoatnation1714]

so if my left driver side is dim would that be low amps and my fog light on the left side wont come on would that be a short or faulty wire

[@Sewnami]

My car shorted out on me. I have a distributor leak and it went to alt then all that electricity went to my alt fuse and melted it. Replaces my alt and as well as the fuses. Ever since I did that, every time I turn the key my 7.5a ignition fuse blows when I turn it over. I ain’t got money to spend on a mechanic rn, anything would help.

[@slengoslengaw8510]

Please can someone answer my question: I have error code 4390=Boost Air Temperature Sensor - Short Circuit to B+. What is the fix ? a new sensor? or wiring? any information is appreciated

[@mk27texas]

Trying to find a short I’m my sons 2006 Corolla. Tail light/dash light fuse blows as soon as you turn the lights on. Replaced all bulbs and checked wires. Still can’t find the short??

[@NickelPlatedProd]

I have a pcm1 fuse on my 2003 avalanche that keeps blowing and I can't find the bad wire