How to Fix Battery Drain in Your Car (Parasitic Draw Test)

Battery drain test. How to fix battery drain in your car DIY with Scotty Kilmer. How to test battery. How to find battery drain. How to do a parasitic draw test. How to use a multimeter. How to find and fix battery drain using a multimeter. DIY car repair with Scotty Kilmer, an auto mechanic for the last 50 years.
Thanks for watching!
⬇️Things used in this video:
1. Circuit Tester: amzn.to/2jGzITr
2. Multimeter: amzn.to/2B1IJ0K
3. Needle Nose Plier: amzn.to/2ic4Olq
4. Wrench Set: amzn.to/2kmBaOU
5. Common Sense
6. Full HD Camera: amzn.to/2AvoEk7
7. My computer for editing / uploading: amzn.to/2i2sKYz
8. Video editing software: amzn.to/2jv5Fhf
9. Thumbnail software: amzn.to/2k7tz6C
🛠Check out my Garage to see what I use every day and highly recommend:
www.amazon.com/shop/scottykilmer
❗️Check out the Scotty store:
goo.gl/RwhRGU
👉Follow me on Instagram for the latest news, funnies, and exclusive info / pics:
goo.gl/ohy2cA
Consider subscribing and press the bell 🛎 icon to be notified of all new videos.
And remember, every day (7 days a week), I upload a new video on the Scotty Kilmer Channel: / scottykilmer
Also, if you like my car help, be sure to watch my live car talk show, every Thursday afternoon at 1 CST and Saturday morning at 10 AM CST on KZbin. I answer your car questions LIVE there. Just check it out at: • Video
Scotty Kilmer is a participant in the Amazon Influencer Program.
#savagescotty

[@scottykilmer]

⬇️Things used in this video: 1. Circuit Tester: amzn.to/2jGzITr 2. Multimeter: amzn.to/2B1IJ0K 3. Needle Nose Plier: amzn.to/2ic4Olq 4. Wrench Set: amzn.to/2kmBaOU 5. Common Sense 6. Full HD Camera: amzn.to/2AvoEk7 7. My computer for editing / uploading: amzn.to/2i2sKYz 8. Video editing software: amzn.to/2jv5Fhf 9. Thumbnail software: amzn.to/2k7tz6C 🛠Check out my Garage to see what I use every day and highly recommend: www.amazon.com/shop/scottykilmer 👉Follow me on Instagram for the latest news, funnies, and exclusive info / pics: goo.gl/ohy2cA

[@alanthorburn5073]

Vegasboy1 Always watch you Scotty on KZbin till the wife takes the tablet of me (I'm 57 for Christ sake) Me ad just have went for a new Battery. Ye that's why the wife takes the tablet of me. I'd have been down £90.

[@j_moravia29]

Hey I have Ford Explorer 1998 I change alterna and started and the the betteries pop up on dash but idk why’s but I need help her new batteries too

[@robertgustamante2426]

Hi had a question about a parasitic draw i have its 700 milliamps how would I find out if it is my alternator diode that is causing it.

[@ridler6453]

The link to the common sense is gone. Must be a hot seller

[@davcot3675]

Is the resistor required ? I have seen test done with out resistor What is the resistor doing ?

[@paulbrowning71]

I always like watching scotty kilmer because he is to the point and does not waste time like the other guy video's

[@garymiles483]

concur.

[@maurauder6762]

Agree and he doesn't play irritating music for 20 minutes before he gets to the point.

[@chanlerfontenot3417]

That’s exactly why I’m here

[@cheekysausage7764]

We in the UK also agree.

[@scottykilmer]

@jptrucker29 Yes, you can do it checking amps directly. This method does it indirectly by measuring voltage with that resistor in place. I use this because direct amp measuring can easily burn out your meter since all the current has to run through it. That resistor I used got so hot during filming I burned my finger. I'd rather mess with a two dollar resistor than a five hundred dollar meter system that I use. Scotty Kilmer

[@KrishnaSingh-ow1ie]

Your right scotty, that's what happen to my multimeeter

[@keithstarkweather3284]

What’s radio shack?

[@user-up6in3sk4s]

lol that aged well

[@mattmccarty72]

These videos are awesome, I think I have saved around $8,000 in repairs on my vehicle over the years by watching and doing most myself. Even if I take my car in to have it serviced, I’m not getting ripped off.

[@seananthony4717]

This has been a problem for months. I just tried your method and found the culprit. Thanks Scotty.

[@DesmoProfundis]

Awesome, Scotty. I was looking to do this test on an '87 Bronco II and was disappointed when you first mentioned that you were going to show us how to do this on a late model car. But I stuck around and you covered the old cars too. Thanks for being so thorough!

[@shellykennedy5427]

Still finding great Scotty older content after seven years of watching. 👍🏻

[@scottykilmer]

check the socket and wiring for damage that heats up and blows it. Also check the charging system, if it overcharges it will do that too

[@moofushu]

Watching these videos makes me want to be a mechanic. There is so much stuff to know about cars. I wish I could know as much as Scotty.

[@scottykilmer]

do the tests in the video for the drain. Normally the horn itself burns out, find it and if it won't honk when you hot wire it with power, replace it. Brake lights are often a bad brake light switch on the pedal under the dash

[@shawnp001]

Hey Scotty, I have followed your channel for years and you have never let me down, in this instance my car is a 93 Corvette so the truck you showed didnt give me results because i was not detecting any drain at all, BUT I remembered what you said at the first part of the video with the test light and it took 2 minutes to find the fuse, now it's all good to go thank you.

[@scottykilmer]

@tearabite yes, but one never knows what the drain is until you check it, so the 10W resistor is a safety method that can be used for all shorts.

[@bottmar1]

I can see where a current measurement and/or voltage drop would be very accurate but I find that a test light shows enough even on newer vehicles since a test light bulb will only glow a little from minimal current flow. (Clock light, computer, etc.) A glove box light or any similar draw that is enough to kill a battery overnight (or sometimes two nights) will cause a test light bulb to glow brightly. I can see though that on occasion there is cause to need numbers, but I have not seen that yet. Keep up the good work Scotty, your advice is good.

[@radioactivelarry]

My drain was the door locks on mr 98 Monte Carlo. I wondered why it was so hard to unlock my doors with the key! The darn power locks were engaging. All fixed now. Thanks Scotty

[@jabbaweezy]

hmmm sounds like the same problem I'm having

[@scottykilmer]

@miguel924 the test would show a draining alternator. There has to be a drain somehwere, perhaps it comes on and off, so test it a few times in different times of the day.

[@scottykilmer]

@MrJeremy313 I never really modify cars. But you just drill mounting holes and bolt them on, then wire them to whatever switch you have, using wiring directly connected to the battery as they use lots of power

[@jmbuchela5424]

OH brother, this is a good one !!!!!! just what I needed

[@brandonlewis2916]

Depending on your multi-meter You could actually just place your multimeter in sequence with your negative battery terminal and negative batt cable. Then just wait 30 mins and check to see what your drain is. After 30 min of waiting for the cars computers to turn off, an acceptable drain would be .003 mv, anything more, you should test your fuses with your multi meter. That way you dont have to unplug all your fuses.

[@scottykilmer]

@contagiousFX this is an indirect way of measuring amps, the two are related and this is the easiest way of testingt them accurately, using volts. Scotty

[@scottykilmer]

@twooger it would change the readings, radio shack sells em or get one online.

[@ryhendo9767]

most mercedes need about 30 mins to an hour for the control modules to shut down, hence, the massive drains you may see. Keep it up Scotty!

[@josehonorato9920]

God bless you Scotty Kilmer ! I love all your videos. Im young and I feel like I'm learning from the best when I watch your videos thank you for making these videos! God bless you forever. I am very grateful just like so many other people.

[@scottykilmer]

@avionicswirenut yes, try that, just disconnect everything you can think of one at a time and watch the readings.

[@scottykilmer]

tons of things can do that, start by pressure testing the fuel pump to see if it's weak. that often does that

[@cinemabunny]

I like the resistor test lead idea with the parallel volt meter. I used the Amperage function of my multimeter hooked in series with the negative terminal. You have to make sure all high amperage accessories are off or your draw may cook the meter (heated seats, fan, radio, dome light door override, etc..). My parasitic drain came from a faulty overhead DVD player wired to an always-on 12v outlet circuit.

[@Jigaboo123456]

Thanks Scotty, this brings me up to date, I would have used the old method, as I'm behind the times. Your presentation style is pretty similar to what I imagine Sgt Bilko would have when he was giving the motor pool a lesson!

[@scottykilmer]

newer models have extra drain, find out what it is for your particular car if it shows larger drains.

[@scottykilmer]

@rosmob719 you have a massive short, first unplug every wire from the battery and fuse box. When it has no drain, slowly put em back one at a time until it gets hot again.

[@yaybeer187]

I love this guy, his videos are corny as can be but he knows his shit.

[@Baerchenization]

Really. Why would you go out and buy a resistor, and start making a crazy cable construction and STILL break out a big ass meter and hook it all up to read VOLTS?! Because you would not. You would spend 5 bucks on the cheapest multimeter instead and not build yourself a crazy resistor and read Amps instead... just like every other how-to ever on KZbin explains... Jesus Christ :)

[@scottykilmer]

cause reading amps is not as accurate. EVERY intelligent mechanic now uses voltage readings for serious electrical work. Even when finding shorts, we all use voltage measurements with a load to test that. You're living in the past man.

[@garybrisebois2667]

A cheap meter will not read current (amps) at all, or will burn out immediately if the current jumps too high even for a millisecond. Reading the voltage across a one ohm resistor is an excellent idea.

[@fritzkeller7567]

Ace Ventura dead on.

[@michellemcneil7118]

Rihanna

[@PnwOnTour]

I had a parasitic draw once, took a while to figure it out, incredibly frustrating always draining more and more but I finally left her and have been great ever since ! 💥 🤷🏻‍♂️

[@erikkafrost3353]

Funny

[@ellenthompkins4386]

😂😂

[@DavyDave1313]

great job at being an incel

[@leesire]

My parasitic weighs about 250 lbs.

[@engrbilalahmedawan1315]

🤣

[@scottykilmer]

@MAIMPORT all batteries come with dates stamped on them. If you suspect one, check the date. Or have it checked with a battery checker, I use a midtronics MD 500 tester. Scotty

[@scottykilmer]

@paulhunter123 it doesn't override anything, it just takes the load of any power drain so nothing melts when testing.

[@abitmurky8365]

Love this guy so much. He has the most informative car videos.

[@bullkaniaupio5585]

What is front control module for

[@jonrob4675]

Wish the original RadioShack was still around 😢

[@scottykilmer]

@humbe23 well, remove the stereo and check the wiring for pinches or splices on the wrong wires.

[@BellaRocko]

Ha! Pretty clever, Scotty. I'm used to hooking up my DMM (set to measure amps) in series on the negative side of the battery. Your method is new to me, and had me thinking until I realized that with a 1 ohm resistor, V=I. So they're equivalent, of course! Thanks, I enjoy all your videos.

[@scottykilmer]

well, do this test then by disconnecting the shift light fuse or wiring and see if the drain goes away. Test, don't guess

[@funnypranker34]

Hey scotty, heres an easier method to test: disconnect the negative battery terminal, hook a multimeter positive on the negative battery terminal and negative to the negative battery cable, set the multimeter to read amps, take note of the number. Then pull out each fuse one at a time. I would start with the fuses in the cab of the car. Once the amperage drops, thats the component thats causing battery drain.

[@rocketmann845]

Peter Kapica miata na!

[@PetrolheadAEHG]

Thanks man, I found the problem in my car with your advise 👍

[@insaini87]

Mine doesn't read when connected on 10 amp setting. Connected properly. When connected on voltage setting it just reads the voltage of the battery

[@mikeedwards2338]

Your way does work but can easily blow your amp meter if your not careful.

[@KrishnaSingh-ow1ie]

That's the way I do it. Much easier.

[@scottykilmer]

@llando17 no, then you have to find what's shorting out in that system by tracing the wring and checking components it runs.

[@scottykilmer]

@mdoyle1268 there are unfused things, like starters and alternators and computers. start unplugging them to see when it goes off.

[@scottykilmer]

then you have an insanely large short there. Instead of a resistor, hook up an old car headlight in line with the terminal and it will shine brightly and you can use that to test is, when the light goes dim, that's the short

[@scottykilmer]

@jvandugan Ah, another 3 stooges fan. I grew up on that stuff, even saw Moe live in buffalo at an old vaudeville stage in the sixties. Scotty Kilmer

[@scottykilmer]

@bhstone1 I would use the resistor, as you have quite a few computers on board that thing. Scotty

[@trucknut04]

Used this method for many years. Great place to start testing

[@scottykilmer]

start by doing this battery drain test, and if you find a drain, do my video "finding the source of electrical shorts "If you like my car help, be sure to watch my live car talk show every saturday morning at 10 AM CST on google events. I answer your car questions LIVE there. Just go to my scotty kilmer channel on youtube saturday morning at 10, and click on the google plus icon on the top right corner. That takes you to the event. You do have to be a member of google plus to ask questions.

[@scottykilmer]

Because that makes the readings accurate due to ohms law. electricity does obey that.

[@dslynx]

AWESOME INFO! Never thought using a resistor and reading the voltage.. Your a goldmine of info Scotty.. Thanks!

[@scottykilmer]

@OutragousGaming sure, you can make it with any kind of light, just get a couple wires and some small clamps like alligator clamps.

[@radioactivelarry]

Bought my resistor on eBay, got two for good price!

[@scottykilmer]

that's full power drain, a biggie. remove all fuses one at a time and keep them all out,then start unplugging, it has to go off eventually

[@jublywubly]

That's a whole lot for this video! One of our work vehicles has had a drain for more than a year. We have to start it up and take if for a drive every three to four days or it won't start. It has a new battery, that I recently had tested along with the alternator. There must be something draining. Now I'll be able to check for the drain, while avoiding an expensive auto electrician.

[@Shamus71]

Thanks for this video, great info!!

[@panzerveps]

Nice guide as always. It's a good idea to lock the car, including the hood lock and let it rest for 10-20 minutes for all of the computers to shut down. There are always some computers that stay on for a while after the vehicle has been locked. These will give faulty readings. I usually let the cars I work on 30-40 minutes just to be sure.

[@jheetman]

Scotty, I've always enjoyed your vids and you totally threw me through a loop on this one. I've always checked for parasitic draw by connecting an ammeter in series, and I am also familiar with checking for draw through fuses. I put my meter on the test ports of each individual fuse and look for a voltage drop, which would indicate that "juice" is flowing through it, since all fuses inherently have a resistance value. Are you doing the same thing here, just at the battery? also, your meter is impressive but a bit intimidating, I understood the Mv readings but maybe scale it down to a laymans meter so other guys can get in on the action too.

[@mmpiforall5913]

+jheetman Actually Scotty should have mentioned the "35 millivolts" is equal to 35 milli-amps ( mA) when a 1 ohm resistor is used. However if you have meter like the one he used, they have a Amps function and you can set the range to measure the current directly - no need for a resistor - so I'm surprised he made the Vid he did.

[@excavatoree]

+jheetman Yes, he's measuring the voltage drip across the resistor like you measure it across the fuses. The voltage drop is directly proportional to the current draw, so it's just as good as measuring current with an ammeter. Because it's a 1 ohm resistor, 1 millivolt across it means 1 milliamp, one volt across it means one amp, etc. I=E/R, and R=1.

[@scottykilmer]

@felipevinalay of course do this test, and also have the battery tested, it could just be wearing out.

[@kongoboi8]

Thanks scotty. I'm having this drain problem. Will try it. Ps I watch all your show just to understand car more.

[@fairouzyousof]

The idea is to measure the current draining. In this case since Scotty has voltmeter, he can only measure the voltage across the resistor. He used 1 ohm resistor, so basically the amount of voltage he measured is the same amount of current draining. (V = I R) But if you have multimeter, meaning you can measure both current and voltage, you don't need the resistor, just put the multimeter in current setting and connect it in series.

[@radioactivelarry]

Been pulling my hair out for months. Nothing seemed to show a drain, then I tried your resistor method. Thanks Scotty

[@lewiskeller8840]

radioactivelarry has

[@Life_Through_Galleries]

What was causing the drain what was your solution to fix?

[@MrNotorius5500]

THANK YOU SCOTTY!! This technique will definitely come in handy to find that elusive parasitic drain on my '98 Crown Vic Police Interceptor

[@nailgunnelli]

LOVE YOUR ENERGY SCOTTY!

[@excavatoree]

you might want to mention that the current draw is really in amperes or milliampers, but you are measuring it indirectly by measuring the voltage across the 1 ohm resistor, which conveniently gives you a 1:1 correspondence. (1v = 1 A, 1 millivolt = 1 milliamp, etc.)

[@dwaynearthur2804]

Just curious, whats the deal with the resistor? Can i just do it the same way without the resistor? Im confused

[@murphyhowey3109]

I would think this method would save some schmuck from blowing the fuse out of his harbor freight DMM when the car is drawing over 10A before it goes to sleep...or melting shitty meter leads.

[@dwaynearthur2804]

@@maxinpains6937 lol thanks alot i appreciate it

[@murphyhowey3109]

@Larry McCraw I was writing in support of your method, and fuses may be as cheap ...but I'm always an advocate for safety, especially when the audience is unknown. Your method = betterer bueno in my book.

[@daviddenson3324]

What's the purpose of using the resistor? I've seen other videos and they just use a multimeter.

[@falxonPSN]

The correct reason is so that he can use the voltage mode on the multimeter which is sometimes more accurate than the current mode. Depends on the quality of your meter. Look at the comment from @excavatoree above for more technical details as to why.

[@leshomorego]

David Denson, I was thinking the same thing.

[@scottykilmer]

realize many devices, like starters, as unfused. You have to unplug their wiring harness connectors to test them.

[@scottykilmer]

@newmanto03 yes, you can use either post

[@Emeliz13]

lmao the intro is funny and lol at "some knucklehead"

[@nydrell1969]

does radio shack still exist?where?

[@sad_boy_scientist]

1969nydrell David ikr

[@MultiThrashed]

I live in SE MA and we have a number of Radio Shacks around here. Not as many as there used to be though.

[@automan224]

1969nydrell David there's a radio shack by my house that's slowly being turned into a sprint store It is taking a long time to happen though

[@mallelathirumal]

1969nydrell David car clutch header cylinder problem in Renult duster india modal RXL diesel

[@MultiThrashed]

Update, Most of my local radioshacks are closing.

[@JetpackSuperheroes]

Scotty, you are a genius!!!!! Thank you so much!!!! Stay excellent man.

[@gomerfa]

This is the most awesome thing ever. Thanks Scotty !

[@yellow6ird]

Lol I came here precisely because of an old Mercedes. Thanks for the tip.

[@frederick6008]

Wow, 13 years ago.

[@scottykilmer]

@24okay yes, I would replace the alternator, that's at least the main problem

[@scottykilmer]

@newmanto03 leave the courtesy fuse out, and if your problems stop, either trace that wirning, or just leave the fuse out. ONly way to fix it.

[@apmirkin]

Wish Scotty was on Top Gear UK.

[@scottykilmer]

So do I, funny bunch of blokes. But the US version is absolute Rubbish. Perhaps you could write them and suggest having me as a guest, I am a rather famous internet mechanic after all.

[@apmirkin]

Scotty Kilmer Sure!! I will try to! However, as you know with the British presenters on Top Gear. None of them talk about the real issues with cars and after care about the vehicles. Yes, you have many many posts and I find your style to be interesting and useful. If you did some kind of unique one off build. I think you would get your own show here. Scotty Kilmer

[@numinous4789]

Great intro vid. This would be a great deal more helpful if you showed effective means of actually tracking down the point of issue, i.e., using wiring diagrams, how to isolate runs of wires, test switches, etc.

[@brandonmusick77]

The video would be hours long and quite technical.

[@scottykilmer]

@winglajones the resistor cost 2 bucks at radio shack, use one for testing. Now if you remove a fuse and the drain goes away, that stops the drain. IF it runs a device that you don't need, like overhead lights, you can drive it that way and it would be fixed. BUT, if it runs something like the ignition system, then removing it will not let the car run at all, so it wouldn't be very useful to do that. Scotty

[@scottykilmer]

@MrTrip3ace bad grounding wires often do that, and there are tons all over that ford. get a schematic showing them all and test them for corrosion.

[@nermaljamslow9024]

R.I.P. RadioShack

[@VictorStoev4]

I cant believe someone took his car to mechanic because his interior light was on and couldnt figure it out

[@mysonspapa]

most likely didn't. it's an example. i have yet to find a video on youtube on how to trace a parasitic drain to a bad ground on a wire. it's always oh on this example its the dome light. gee thanks huge help, not.

[@trance20001]

@ Tim McQuate - When you find the drain, why not make a video and help people who didn't get helped from Scotty's videos. I am not holding my breath over your video coming up anytime soon.

[@rezagrans1296]

@Tim McQuate exactly the iver-simplif i was shaking my head over. Just likes profs in universty

[@rubyallen3169]

@@mysonspapa watch scanner danner he can help u out alot with electrical issues

[@michaellapierre1244]

Hey Tim - Here's the technique to answer your question. First test using the 1ohm, 1000W resistor like Scott said in the video. He said up to about 35mV across the resistor is acceptable. So if you read 35mV, you know you have 35mA of drain current by ohms law. See my previous comment if you need that explained. At this point you know you have a leak, you just don't know where. So start pulling fuses to try and make the current flow stop like in the video. If that does not stop the current, then it should be leaking back through the diodes in the alternator or the problem is between the battery and the fuses that you were pulling. So, disconnect the alternator wires going to the battery to test the diodes. Otherwise, you have a skinned wire shorting to the chassis between the battery and the fuses. You called it a bad ground. The easies way I know from here is to get a DC current clamp and start testing each wire as is splits off from the battery on the way to the fuse boxes. Hope that helps.

[@scottykilmer]

that means a relay is turning on and off, so check that first, though some cars will blink for a few minutes then stop, and that's normal for them

[@moonshinegrrl]

Thanks for the instructions and for making them simple

[@GRUSSNewton]

Scott's on some serious drugs!

[@erikkafrost3353]

HATER

[@scottykilmer]

@avionicswirenut often a bad alternator, check that out too, places like auto zone check em free in their parking lots.

[@scottykilmer]

@lcw1980 It is IF you have the radio turned on, listening to it. But if it's turned off, that's WAY too much drain. Scotty Kilmer

[@scottykilmer]

@langtana do this test and fix any shorts that make the light come on. and of course, go back in the dash and see what wires he crossed up

[@scottykilmer]

one, have the alternator checked first, rebuilt ones often stink and dont' work right. Auto zones check em free. But if it is good, then you have a wiring problem in the charging system

[@scottykilmer]

@andrewmylyf ecus often drain a little, but only 5 or 10 milliamps.

[@scottykilmer]

@890buba wiring , bad battery, or bad alternator cause those codes. so check that first.

[@ThunderHead289]

you sir have most likely forgotten more than i know. this is so simple yet brilliant.

[@scottykilmer]

that's a transmission control problem code. but flickering is often weak battery or alternator, have them load tested.

[@scottykilmer]

@hp11208 It works for ANY 12 volt system, car or otherwise. Scotty Kilmer

[@scottykilmer]

@johhny6gun yes, it has many computer systems that would show a normal small drain. Scotty

[@scottykilmer]

@gunmetalx because this is easy, and safer for equipment and the parts are really cheap.

[@FatbikeRepublicNL]

Thanks a bunch Scotty. We we finally able to track down the parasitic drain on my wife's H3. BCM module.

[@mohdzhafirin1498]

Baguih naaa hang buat video yang bagi manfaat kat orang lain... walaupun entuism nampak lebih, kira ok lah xmcm saya passive, nak shows,all out tak sampai 100%. 50% pon x. Bukan below average lagi dah, below abnormality.

[@adriantomlin2902]

Thanks Scotty! I have a an 89 Silverado and now I know how to check for a drain

[@theGADGETSplaylist]

I'm going to make one of those test cables! 1 mV drop across resistor = 1 mA draw...you got to love it. Amazon has resistors. I may mount that on a small piece of wood to prevent stress on the resistor wires and solder joint. Won't solve problem if it's a bad alternator diode though but it's a damn good start at eliminating all other possibilities.

[@scottykilmer]

@MultiPanther2000 Do this test first, and if disconnecting the blower wiring stops the drian, that's the problem

[@scottykilmer]

@duydadance answer: well, either you're getting crappy alternators and batteries, OR you have a wiring short in the charging system. Normally just bad alts on those.

[@maurauder6762]

Scotty I appreciate your knowledge, and like your videos, thank you.