How To Perform a Parasitic Draw Test - EricTheCarGuy

/> This video has been a long timing coming and is one of the most requested things I get is about batteries going dead overnight so I'm very happy to finally bring you this video about the process of finding a parasitic draw which is a small drain on a battery above 50ma when the vehicle is shut off. Once you find the right fuse(s) the next step is to trace the components involved in that circuit till you find the source of the draw, you first start with a wiring diagram to give you an idea of where to start looking and then start unplugging things in that circuit to isolate the cause, it's quite scientific really a simple process of elimination. Here is a link to BBB's site that you can use to look up wiring diagrams for your application. /> Good luck and if you have anymore questions check the database on my website and if you don't find what you're looking for there then post your question to my forum, here's a link. /> --- Click below and Stay Dirty Visit me at /> Visit EricTheCarGuy Forum /> Visit my Facebook Page: /> --- Be safe, have fun, and stay dirty ETCG Due to factors beyond the control of EricTheCarGuy, it cannot guarantee against unauthorized modifications of this information, or improper use of this information.  EricTheCarGuy assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. EricTheCarGuy 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 EricTheCarGuy, 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 EricTheCarGuy.

Jaron Lindow
You left your dome light switch on. That'll be $180.
Cameron Alexander
Ita always the last fuse you pull...
George Last
Hi everyone, I have this same problem on a 2003 mercedes c230. I pulled every fuse and couldn't find the problem until I started pulling connectors from the dash, then I found what was drawing 0.96 mila amps and draining my battery and sometimes killing it completely, it was the DISPLAY PANEL with the triangle on it for the hazard lights. AS soon as I removed the smaller plug on the panel the amps dropped to 0.23 please keep in mind that my digital meter only has 3 digits.
Jerritte Couture
This video came in SUPER handy today for me. After replacing a bad battery a couple of weeks ago (it was tested and had a bad cell...about 5 years old), I tried to start my car today after it had sat for about 2 days, and it was completely dead again (lights wouldn't even turn on at all). I didn't have to test the fuses, because now that this was the second time that a battery completely drained (and this one was brand new), I knew it wasn't just a bad battery. I tested the alternator after I started it with a battery charger/starter, and it tested good (14.48 V). After that, with the help you provided here, I tested to see if I had a draw. I did -- 1.35 amps. I then coupled this information with odd behavior from my CD player that I hadn't had time to investigate yet. Whenever I started my car, it would eject the CD. With this information, I checked out my stereo to see if I could find anything wrong. Sure enough, the eject button was stuck pressed in. After pressing it several times, I got it to unstick. I continued to press it in and out to make sure it wouldn't stick anymore (I'll spray some lectra-motive cleaner into it later). Once it stopped sticking, I rechecked the draw, and it was GONE. Woo hoo! Thanks a bunch for posting this video! Though I didn't have to go through the process of checking each fuse, the overall logic got me to the solution WAY faster than I thought I'd find it. This took me a total of about 20-25 minutes, not including the time to watch this and a couple of other videos. You saved me a bunch of time and headache, not to mention possibly some money, had I ended up taking it to a shop to see if somebody else could figure this out.
Joshua Taylor
Hey Eric. I'm 6'8" tall and weigh around 360. The point in trying to make is I don't fit in most trunks very comfortably, much less a glove box lol. One of the methods I use is to set my phone to record place it in the trunk/glove box/under hood. Aimed at the light bulb. Then close the unit, reopen and observe the footage Saving the fire department from having to use the jaws of life to get me back out.
Ray Wolf
You just saved me a crap load of cash. Thanks Bud
Scott Leachman
I learned more from this tutorial than any other viewed over the years....THANK YOU. I now subscribed!
man, this guy is as cool as a cucumber.
Stephen H
I swear they keep adding more electronics to vehicles just to keep people from doing their own repairs.
A Christian Jew
Great video! I have a XJ Cherokee that drains a battery in less than 2 days, did the amp test as per your video and it is drawing 3.9 amps! No wonder it's killing the battery. Did the fuse pulling in the engine bay, no drop in amps, will do the fuses under the dash in daylight, and when the rain stops. Thanks again for your very informative video, will thumb up!
Sean Maher
I invested in a mutimeter, watched this video and found the problem (The dash clock). Thanks. Eric.
Han Skinslo
This really helped me find the parasitic drain on my wife's '96 Pontiac Grand Am. Too bad it won't help me fix the rusted out engine cradle and rockers!
How would you perform this test on a new vehicle with dual batteries? Does that even matter? Vehicle in question is a 2018 Ram2500.
Allen Mundorff
Sorry to hear the door switch is depressed at 7:29
Michelle Ciardullo
Great video Eric! Thank u for explaining this in layman's terms. U made it very easy to understand & identify a parasitic draw. I wanna marry this guy. #genius ☺
Pedro Talavera
Sup Erick? Great video like always. I had to send this to a guy customer so he can see that you use amps not volts to test for parasitic loads. He think he knows more than me. Don't know why he hired know the type
James Mendoza
My mind - much like the damaged fuse I found - was blown. Thanks Eric! Edited: Actually, I was wrong. It was a blown dome light that was ON for me too LOL
bobby redondo
you are another of my heroes.A man's man. thanks alot. you are a super helpful person. I don't know what's in it for you, but you should be rewarded for all the help you provide. Donyboy73 is another. thank you Eric. You should have your own show.
Suren Bono
...add at least 18 v 10 amp solar panel ...on the would fit the roof..mine is like 60cm x 30cm dimension.. connect it to a charge controller to your will wipe the entire vampiric power drain by recharging free by the power of our star...why did not any engineer think about that...its starts and stops automatically. when there is visible light...even an artificial light will do....dont have to worry about drained battery forever...peace out...quote from a vamp hunter south east
Bill Wollman
Thanks so much for this. I had my '08 Acura TSX (notorious for battery drain) tested for parasitic draw at a local service station; they claim to have found nothing. When the battery they sold me three months ago died, I followed your video and confirmed that the Hands-Free Link was drawing 230mA on its own. Disconnected it and now have a normal car again. Great job by you.
Raksa E36
Hey Eric my ford 12 flex have bad drain battery when I use Parasitic Draw Test I found fuse: #5-Brake transmission shift interlock(-0.20amps) drop after remove fuse #14- Center information display,(0.20amps) drop #25-Demand lamps(0.10amps)drop #26-Instrument panel cluster (0.30amps) drop Do I need to replace those part to fix it ? Thank you very your helping me again
John5444 noway
Thank you so much for your time . Really great information
jerome focosi
Thanks Eric, So glad you did this on my engine. It also was the overhead door/dome switch. I see 548 negatives , dealership techs, no doubt.
Tayvin Thompson
Eric your giving away knowledge for free and I am consuming everything. Thanks bro 👍
Hey Eric I have a quick question... So what if your door switch is bad while your running in series while the meter is still connected? Could that short out the meter?
James Mcbride
Great explanation and very informative, clear and concise, covered some drains that you wouldn't no about on newer upmarket models. brilliant. ! One thing he did not cover though was a drain in the alternator regulator
Tony Attard
Hi, What is the brand name of Amp/Volt meter?? Thank you. Tony
Rick Rose
Best video I've found to diagnose wiring problems, Thank you Eric, thumbs up
Ricardo Volkmann
Thanks for the information it really helped me figure out what is going on with my parasitic energy draw.
George Spangler
I do the same thing useing a test light on negative side,,can't destroy meter with it.
So the switch was on but you didn't see interior light on? what was the final finding? Something in the radio was bad? I'll be checking my meters for amps. great info.
Do you really have to start this fuse-pulling test with a fully charged battery? And also, what about relays?
Cole Harris
My car (BMW) just read over 7.0 lmao... no wonder my battery dies after 2 days without driving it.... haha... imma find this parasite and give it some some antibiotics.
John Lee
Thanks for the great video. I did as you said, i think. I set multimeter to 40mA, the multi meter read between -11.6 - -12 mA no matter which fuse or relay i pulled. My battery seems to be loosing less than 1 volt during the night. Does this seem like i do not have a parasitic draw? I keep burning through parts stores alternator on my 7.3 L diesel 2001 f250. Thank you
Dennis Silverstein
This is the best guidance I have seen.. I fully understand every thing - being you actually showed us, not just told us :) Thanks.
Moises Saenz
great video. could you please make a video on how to use the electrical diagram to fix the problem if its not just a switch that is on....
Rickarama Trama
Super good tutorial and I learned a lot but God help us with these high tech cars. When I was in high school my 1953 Chevy pickup had >(2)< fuses and I drove it for 6 yrs. with no blown fuses~!!!
jericho tm
thanks so much! I know now how to check the amps with my multimeter! This was very valuable information, so thanks again! Ta, ta!
Patty Daniello
Because of your video, I fixed my battery drain. The amps dropped with the radio fuse out. I guess that's a common thing. So I am keeping the fuse out. No radio but have a running farm truck. Thank you!
David Williams
That was awesome Eric.I am a former electronics tech and you reminded me of many things that I had forgotten. Especially disabling the door light switch. I watched another video and I wasn't following what the guy was doing with the door switch and my odyssey has so many lights that come on when the door is open, that probably would have ended my multimeter. thanks.
Aa Bb
Dude that intro was priceless! Had me cracking up lol.
yyy yyy
Excellent articulation on the process for trouble shooting parasitic draw. Keep the videos coming
Thanks a lot ! I found my parasitic draw - defective webasto heater - 0.64 A
Philip Tye
I always used a test light, unhook the ground and hook up the test light between the ground cable and the battery ground. if there is a draw the test light will be lit, pull use fuse at a time until the test light goes out then you know the circuit you need to examine 
Brother John's
This a really good video. SAVES MONEY AND YOU LEARN!
Gorilla Z
Your video helped me fix the problem with well taught, simply said instructions. Fortunately for me it was literally the first fuse I pulled in the fuse box under the hood of the Wife’s suburban. Turned out the radio was drawing around 2.85-3.20, I pulled the fuse out and it went right down to zero and stayed at zero. Thanks again for another great tutorial. I’ve fixed my vehicles from at least 5 of your videos, such a priceless thing you are doing for us man. Please keep it up!
Cobra J
Good advice about suspecting after- market ANYTHING electronic. After market light installed underneath my pickups tonneau cover was left on. Ruined battery
bomark 2002
Ok George Clooney give it up!!!!
Daniel W
This is one of the best videos I've seen on YouTube, very informative. I feel much smarter now, thanks Eric.
Philly Jay
hey Eric, great video!!! My battery has been draining overnight and especially in winter time. I bought a new battery six months ago and the problem is still persist. I followed your instructions and I just literally checked for any amp drain and I'm not getting any reading on multimeter. what is causing my battery to drain out? Thanks, Phil
This video is exactly what I needed to see. My battery drain happens over a week's time, I drive company truck so mine just sits From weekend to weekend... And when driving , i stop at a stop light and voltage drops significantly and almost Peter's out...I replaced battery, added higher amp alternator, 0-guage grounds for engine and battery to chassis as well as new fusable link and fused 0-guage charge wire from alternator to battery...has not fixed the issue. This will help me track down where the draw is coming from...thank you for making this video..I may not find the answer with this test but I was out of ideas untill now. And this seems like it will get me closer to pin pointing the draw...thanks again
Bob Miller
Excellent as always. In fact, I've found your videos to be among the best of it's type on YT. I had to laugh, though, because the problem in this case turned out to be the interior lights being left on. It's probably a good idea to look for lights being on before doing more elaborate testing but I'm sure you just did this to demonstrate the process.
What if my multimeter is a Fluke 70-III Series and it doesnt have the amp settings
nitrams world
good job.. new car go to "sleep" when the capacitors discharge.. fyi..
Brandon Scheuvront
This is a great video Eric. Man you've come a long way.
Nunofyour beesiness
This was definitely the best way to find the culprit causing the drain,for an amateur.Thanks Eric
Uggghhhh... This is why I hate modern vehicles. My 48 year old truck has like 5 fuses in the whole system.
Stanley Tolle
Here's a little tip to protect your app meter from shorting out. Actually the meter already has a fuse in it but often it's a pain to replace it and you also need a special fast blow fuse. The fast blow fuse is important, can't get it at the automotive shop. Most cases the meter case has to be opened to replace the fuse. To ovoid all this put in a sparkless or electronic fuse inline with the meter leads, a few amps lower than your meter's rating. Don't use the thermo breaks you normally find at the auto parts store. These are for head lights. What you want is the sparkless or electric type used in racing. You can find them for a couple of bucks on-line. These breakers prevent sparks when wires are shorted to ground and reset as soon as the short is ended. Good idea to use these fuses in jumper wires too. In fact that's what I use is a jumper wire with one of these fuses in it for amp readings. Makes allot of electrical work safer since sparks are prevented when shorts happen.
Cullen John Davis
I should pull the relays in the fuse box as well right?
Ken Marriott
Would you disconnect alternator red lead first to check for bad diode draw?
Barry A.
'When you disconnect the battery on a modern vehicle, one or more modules or components that might have been awake and drawing current might be put to sleep, temporarily eliminating the very parasitic draw you were attempting to locate. Pulling individual fuses that feed one or more components has the same problem as disconnecting the battery, albeit not as globally. So how do we locate the offending circuit without powering down that same circuit using the older power disconnect test methods? We measure the voltage drop across each of the fuses. That's right, even a fuse has some resistance when heated due to current flow across it. This means the fuse that has current flowing will have a measurable voltage drop across it.'
haroot pashayan
scientific precision in explanation, thank you
Wallace Rollins
Does this test work with testing Relays (AC, EFI, Fuel Pump, Memory, etc.) as well, or is there a different test/procedure?
Steve Allen
Hey man, Best vid I've seen on this subject. If you're ever in South Australia consider a cold beer waiting for you.
Thanks Eric, love your videos! Very helpful
Denise Koopman
Thanks Eric for your easy to understand & easy to follow videos. This is another great diagnostic video that helped me figure out why my battery keeps dying. You're the best!
Vincent Griscavage
Very nicely done, thorough and comprehensive.
Excellent informative video. Very technical with true troubleshooting techniques. Good engineer with a solid background. Best on Youtube for professional vehicle repairs.
Personally, I rather have my driver side switch disconnected. I can't stand the chime and light draining when the door is open. I have a separate pin switch for the alarm. I tether the wire with electrical tape for easy hookup if needed.
Steve Shaw
Thanks so much for the logical process using my VOM. Was able to locate the source of drain on my daughters 82 Mercedes Diesel recently purchased. Only took 10 min of setup and fuse pulling! On suspect circuit, found a broken head off a fuse that fallen (w/P.O.) arching between two circuits. Great feeling to get this w/o big shop fees!
Bob Calgary Canada
Very Detailed explanation Thanks for sharing
You are the man! Well done mate. Thank you for the info! Keep it cool and stay dirty!
Condee Rogers
I checked every fuse and part and could not find the source of the draw. I did notice that my multi meter fluctuates amps. From 1/2 to 3 amps. Also my gas gauge goes nuts when I first turn on the key then goes back to normal. Pulling the fuse didn't help. Any ideas?
Adrian Decu
Thanks a lot! Was very helpful!👍👍👍🤗🤗🤗
Ellis Wildman
I always found it better to never fully remove the negative terminal before connecting the leads or it won't get an accurate reading and have it set at milli amps.
Cyrus Monterola
2012 but still is helpful for me in 2018 :) Thanks Eric!
Reserved 100
How do you test for parasitic draw on vehicle with two batteries? I have f250 and batteries are new but I have a problem starting the truck after little while
12:10 - The magic number? ... 50ma (holds up 6 fingers).
Chris Angelastro
Thanks. I have the same condition in my 93 Mustang. Now I know to troubleshoot the issue. Thanks again!
snoboy 58
Eric, you are one of the best YouTube educators out there. Thank you for these most excellent vids.
Michael Gaweseb
I struggled with alternator not charging for months lost a new battery and all the lights. I kept digging after bench testing both starter and alternator. I realized upon inspection of all the wires connected to the alternator that the small wire switching the dash light on was broken. Tight it together and everything was ok.
Bill Houx
Great video. Clear and concise. Thanks for posting the video.
Excellent video with in detail commentary on parasitic battery drain issue. Thanks for posting!
Don Giusto
Very good info here. Good job. Thank you BBB.
Hi again Eric, mechanic could not fix parasitic leak.
Emmanuel Samaras
You are so correct. My GeoMetro showed voltage reading when I connected the negative post of the battery to the negative disconnected battery lead
Pete Butler
Eric, YOU FIXED THE CAR BETWEEN 3:37 and 3:41! Haha, I know it's about the troubleshoot
Excellent, thanks for sharing
Sky Flyer
The one main concern of parasitic draw is the damage it can do to your battery if it draws long enough to drop the voltage below 11.8V. Going below this point will damage the batterys internal structure permanently. Do it just a few times and the battery will be destroyed. If you know you have a sizable draw and can't spend the time to track it down you can do one of two things. Disconnect the battery when the vehicle is not being used OR attach a trickle charger to the battery to keep it topped off and compensate for the draw. The worst case parasitic draw: When you continue to drive your car after the alternator light comes on. Your car is running on battery power alone and will likely toast the battery.
"Start with the highest setting." No, start by making sure all the switches on your dash are off.
does it matter if there is KEY near?think it activates car ecu thus consumes power.or should i wait 20 minutes after ignition off?
D Kat
Down right best parasitic-draw video made ....I keep coming back i forget to much.
James Ebola
If that switch was on, interior light would have been on also. Sounds to me you did this on purpose to make this video. Also, today's radios always draw current, for presets and theft protection. If the car is garaged for 2-4 weeks radio will empty the battery. Otherwise, good job explaining stuff.
Abel G
Put mine on 10A on multimeter & read .75 A quarter above .50milliamps is not bad is it? The batterys do go about 10.9 within a day if i dont crank it.
Reese Blenkin
Super helpful, thank you very much Eric!
Tony Attard
Thanks a bunch Eric. Best video ever. Tony
Great info  Eric thanks covered  it  all  [  25 year  Ford Lincoln Tech   handle  SERVICE PRO]
I know this is old but it really helped! God bless!
djmisterjon dj
OMG tanks a lot my friend, now i will can try found this %$#^&*$ :)
Cornelius Small
2nd video today that may help resolve my 91 acura legend troubles. shops wanted to charge $75.00 an hour. I need to go buy a meter but I suspect its either the after market radio or a blown light stuck on somewhere.