Diagnosing Alternator Problems - EricTheCarGuy

Visit me at: www.ericthecarguy.com/
I got together with my friends from BBB Industries on this one, we managed to put together a pretty comprehensive step by step on what to do if you suspect an alternator issue. Take the time to go through these steps the next time you suspect a bad alternator and you just may save yourself a trip to the auto parts store.
www.bbbind.com/
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Click below and Stay Dirty
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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.

[@sonofmaniam]

I do almost all of my own work on vehicles now. Just wanted to say that this video is the one that really started it all. Before this video, all I was doing was oil and brakes. I used this video to fix my first alternator problem. I bought a new alternator (like a typical swapper!) but because of this video, that part sits on my shelf brand new to this day. Because the troubleshooting (and specifically the drop tests) helped to definitively locate the source of the problem, which was a loose and dirty alternator hinge bolt on my 2004 subaru outback. Before then, I didn't even own a multimeter, and I literally had to walk step-by-step through this video. The tests help literally isolate the problem down to just a few inches of possible culprits. It totally changed my thinking, and ignited my interest in learning more. I have since done the water pump timing belt on a 2003 v6 Accord, axle ujoints, hubs, rebuilt drive shafts, installed lift kits, and helped a lot of people not get screwed by shops. I plan on making this the year that really increase my electrical diagnostics skills. I have a 96 Cherokee XJ that I love, so it will be enjoyable, but probably also necessary to know. Taking an old Jeep to a shop every time you have an electrical problem is a good way to go broke, and not have your vehicle for weeks at a time.

[@missberries214]

Im about to join you,I too like and enjoy this video and am hopeful to get to the bottom of my issue by using this video. 2003 Mitsubishi Eclipse GTS V6 5-Speed At first the Alternator would work sometimes now it completely died,Im not sure but I suspect the previous owners wiring charade was the original cause.Theres an amplifier hooked up that constantly drains even with the ignition off.I have a son on the way,and I have to get this fixed asap before Every dollar gets spent on the baby lol. Im going to just replace the alternator and hope for the best,But will be testing the new system using this video to hopefully pinpoint any problems I might have.

[@colterino]

Yup..amazing, right...do all my brakes now (Honda Pilot...saved me what ? $2-300, labor ?) ...and did This Check...Feels good, right..ERIC Saves Us Bucks...and Empowers DIYers !...Kudos, Eric the CarGuy !..THANKS !

[@chrisvocatura1112]

Jordan Moore

[@kemeticreality8945]

Good job

[@jimbridleman6261]

Close

[@jasonwilcox2245]

As an Industrial electrician, I learn something new almost every day. Your videos on car troubleshooting are great. Keep up the good work. A video on how to replace the battery cable to the alternator on a 1998 Audi A4 would be sweet.

[@guntheriv5926]

l

[@salsarriba5695]

this is 9 years but the youtube search brought me to one of the best car mechanic on yt. even these days there is nobody who can lay it out better than this guy ..

[@KENFEDOR22]

Great video, Eric - always start with the simple reasons: corrosion on battery terminals, loose connections, loose belt. There it was - loose belt. $7 later alternator properly recharging battery.

[@markmarchand8376]

I keep coming back to you Eric......As a mechanic I have varied responsibilities with a multitude of equipment. I need to stay on top of things and you are one of two persons who I watch regularly. Dan Sullivan being the other makes it possible to stay informed. Thank you

[@georgea0731]

Great video, Dealer said over $500 for alternator part only, Advance Auto re-manufactured one was $130 w/ core. So far the new alternator is fixing the problem.

[@modscientist9793]

Thank you for this! I took me all of ten minutes to diagnose and fix my no start/weak start condition. All it took was multimeter and a few minutes to patiently probe everything I needed to look at. Saved a ton of money. Started at the battery like you said, checked for proper voltage off and with the car running and a load put on the system., then removed the terminals,.cleaned up the wires, terminals, and posts, reconnected everything nice and securely, fired it up and without hesitation, she came to life purring like a kitten. Went through the rest of your steps, then last, went to the alternator, serpentine belt etc. and tested them for proper tension, readings, and operation. They also passed with flying colors. Took her out for a test drove close to home several times after the fact..all is back to normal. Amazing how a little corrosion on the battery terminals could wreak such havoc on a system, so I also checked all of the wiring for good connections etc.. A nice wire brush and even some contact cleaner got everything looking spic and span. Now to solve my door ajar light issue lol! please help. I tried lubricating the door latches but I'm still getting the door ajar light,.had to remove my dome light bulb. It was killing my battery. Doors are closed but the light would stay on.

[@duderama6750]

Could be a broken door sensor wire in the harness to the door.

[@jasonbrown467]

dude, i appreciate all your videos. you start with the basics, discuss theory of operation, cover variations and then work your way through a logical flow chart all the way to the end and then beat on things to not over look and then conclusion

[@rodneybrimer1712]

Thanks , I was showing bad alternator, I got new one put it on. Same thing. Watched your video I found a ground issue. Quick fix now it's working great.

[@anthonym612]

I think Eric is my new favorite person on the internet. He's damn good at what he does and puts out really helpful videos.

[@eddywade5346]

Thanks!!! Your videos are consistently the best car videos I've seen around. Good solid advice and how-to's, with specific information such as what's shown in this video. I learn something everytime I watch one of these, and my wheels are still rollin'. Thanks a ton!!!

[@redhoggin0714]

Tapping the alternator causes the brushes to temporarily make contact. One mechanic to another, Awesome video Eric. You explain things very well,

[@mikekoenen77]

Thanks for posting this video Eric! You've inspired me to learn about the Multimeter I've had for 10 years but haven't taken the time to educate myself about it, and how to diagnose my 2004 Santa Fe alternator/battery problem. Keep doing what you're doing ;)

[@StephenVieau]

you're like my old shop teacher! but not drunk :) good job :)

[@phildonnakilmer5109]

Our shop teacher drank Listerine

[@RedEyedJedi]

I am so happy I've found this channel. I love doing work on my own car and have been increasing my collection of mechanics tools. I recently just changed the valve cover gasket on my car which on a normal car wouldn't be that difficult but my car is a VW Scirocco 2.0 tsi and it doesn't even have a gasket. It uses anaerobic sealant. To get the valve cover off, the vacuum pump, hpfp, pcv and upper timing cover needed to come off. I'm watching every video you have made Eric and I hope you keep making them because there is nothing better than being able to fix your own car. Thank you so much for the time and effort you out into making these videos. Take care and stay dirty.

[@janslos]

Eric, y're my hero, had some problems with charging, removed the alternator, tested it inside - outside, shit could not find the problem, finally I decided to search your channel, and there it was, the mass cable between the engine block and the body was corroded, I had a voltage drop of 1,6 V with almost everything on and the engine running idle, it went to the roof when I turned up the rpm. Thanks man, you saved me a lot of money again.

[@ChumpusRex]

Just remember that on many modern cars which have ECU controlled voltage regulators, the ECU may sometimes deliberately request low output from the alternator. This is often done to improve fuel economy and to prevent overcharging, especially when idling, when the regulator will be dropped down to basic battery voltage of about 12-12.4 volts. I know on my car that after the engine has been running for more than about 10 minutes, the battery voltage drops from 14.5 to 12.4 volts.

[@guubagaaba8391]

great video !!!! i am a tech for over 25 yrs.,but still like to watch back to the basics videos just to keep kinda brushed up !!!! however, as far as the computer controlled voltage regulator, i've only really seen dodge to be the worst !!!! and of course most customers don't believe you and go some where else !!! after that ,....who knows what happened !!! thanks for your videos !!!!

[@rosedyno465]

That video was very helpful.Thanks

[@akuma6099]

Great video, Excellent troubleshooting flow chart. Thanks for the tip of checking differential voltage on positve/negative sides. as for oddsn'ends comment below: The author doesn't mention disconnecting your battery while running because this method if frowned upon with newer vehicles. That test can actually blow components. The battery acts as a filter cap and when your alternator spikes to 18v even for a nanosecond, you can potentialy destroy electronics because they operate at 12v with a small tolerance. You could get away 13, maybe even 14.5. It is dependant on the circuit and is risky even though it may seem to work. On older vehicles like mid 90's and below no problem. The test methods provided in this video may take an extra minute using a multimeter but it enables acurate diagnostics and less work. You don't need a socket to pull a terminal. That saves time. Thanks EricTheCarGuy!

[@SLOTERification]

Thanks Eric!! You're very helpful in your comprehensive explanations. Helping me heaps at Mechanics school!!!

[@davidmcdonald8027]

Very good instruction! Thank you Eric for taking the time in putting this together.

[@insylem]

Thanks Eric! I thought about a ground volrage check before, but I never knew what would a normal or "good" reading would be vs a bad reading :)

[@butch2700]

Scotty you are main reason why I stop taking my car's to mechanics.Stuff that I thought was hard to fix you made it look easy.Just watching your videos did the trick. Thanks for all the videos.

[@paula2917]

his name is actually Eric

[@petertropp7676]

Well Eric you saved the day. I had coolant issues with my 2001 Honda Civic. besides the cooling fan the thermostat was not working right.The thermostat was new. After watching your video on thermostats I found it was with that little value on the bottom. After the thermostat was put in THE RIGHT WAY all air was able to be removed.This isn't about alternators but thanks so much. By the way I have a 1956 firetruck that is positive ground. I had some charging problems. You videos have helped me out. Thanks.

[@restore64]

Your videos are always a great help. Thanks for dedicating so much time to make these. I run a lot of electronics in my vehicle and my Honda only maintains the battery voltage it doesn't really charge it. I also need a HO alternator and was curious if a self exciting one that constantly ran at 14.8v would damage anything?

[@joeG9100]

Great Video very informative. The only thing I saw for a recommendation is when Checking for voltage drop. You should set the meter to 2V not 20v, though in this case it would still pass. The meter should give you one one more digit of resolution in the 2V range.

[@michaeltrumbo5223]

I recently started doing as much work as possible on my own cars. Recently the battery light came on in one of our vehicles, I found this video, and solved the problem in just a few minutes. I was ready to go get a new alternator. After walking through all of the steps, I discovered that the belt just needed to be tightened.

[@AvatarBuddha781]

*Thank you* for that wonderfully detailed, knowledgeable and extremely useful helper on diagnosing alternators. Love it! A++!

[@7usu7isso1]

One more test to do is to measure the AC voltage across the battery terminals while the car is running. It should be zero, but if it is higher it means a diode is no good and needs to be replaced. Great Video!

[@dylanboxler5784]

I swear, eric always seems like he's about to bust out laughing hysterically

[@mortali6796]

Lmao 😭😭🤣🤣😂😂👏👏

[@davidwright873]

he's too jovial for sure.....Maybe he needs meds? bring him down a bit..? smart AF imho tho....

[@mikem5475]

@@davidwright873 Haha pills fix everything don't they? Maybe you need some to humble yourself

[@-MightyJoeYung]

This is the best comment on the internet 😂😂

[@JohnIvoryMusic]

Now I can’t unsee it lol

[@skipperandy2199]

This truly is a great video. Nice refresher course for me, since I do do my own work, but not regularly, so I forget a few things, this video helped me refresh my knowledge. Thank you very much.

[@jumpers3]

Thank you Eric,you made it more understandable for me to wrap my head around my problem with my 1984 toyota camper that's on the 3rd alternator voltage problem/parking lights/volt light on !

[@goonergooner3572]

Eric this is phenomenal stuff! These videos are really great, and I'm learning so much! Keep them coming!

[@sambell385]

That’ll be $5000 please😁

[@PaulT08]

This video was awesome. Thank you so much Eric!

[@driver902]

Great reminder about checking ALL connections first. Got a 99 civic ,and the alternator is BURRIED !! Thanks Eric.

[@shdwban4posting279]

I haven't fixed the gauge yet, but I think that is the issue on an older truck that I have. Saved me about 40 dollars in parts and the grief of replacing those parts. Thanks Eric.

[@harrylindanicholson3351]

Eric. I have great respect for your diagnostic events. Working on a 2006 E250 Econoline 4.6L Van. The alternator gets very warm even with the engine not running. Engine cranks, won't fire. No spark, no Schrader valve found to check fuel pressure. Tried quick start but nothing of course. Replaced Alternator (tested and found faulty) after it fried the battery and lights came on very bright in cabin. Truck finally died and was towed here. Rebuilt alternator is also very warm without engine ever running. New Computer NA. Thoughts?

[@liveandletlive2894]

🤷‍♂️

[@ynef]

This video just saved me from buying a new alternator. Turns out one of the wires had broken inside the socket so it wasn't that obvious at first glance. Thanks man!

[@Evo_Spec]

I've been a long time subscriber and I'm glad I decided to check your video before buying a new alternator! Saved me some money and time, only needed to clean the contacts!

[@gabrielarchangel381]

Thank you for the help using the meter to check the alternator for charging, you are the man!

[@JosephusXIX]

Great video. Very thorough. It looks like the positive side voltage drop part wasn't included though.

[@mrbreezeet1]

No, It WAS NOT. I Ass-U-Me it is done the same as the negative.

[@wmichaelbooth]

It's not done the same as the negative. The positive side is tested between the positive battery terminal and the post on the back of the alternator, the one that was a wire bolted to it.

[@byronbates8974]

This point is stated in video.

[@truckinjeff]

One thing you missed is that some instrument clusters have a charging system trouble light with a resistor wired in parallel to that light. The light and resistor always has battery voltage to it (probably through the gauge or cluster fuse) when the key is on. The ground side of that circuit goes into the alternator through a plug or a terminal on the alternator. A malfunction in this circuit has caused alternators to not charge. So if anyone has a setup like that check the instrument cluster.

[@johnrhornerjr4828]

Eric, Thank you for your excellent videos.. I have learned much, enough to keep my old car running... Job well done!

[@rick7684]

Every sense I found Eric videos I enjoyed them and has helped me by watching them, Eric tells and shows right down what and how to, As a rating A+++!!

[@jerebuck]

Great stuff, thank you Eric.

[@grandprixuse]

I cleaned the bolts that hold my car's alternator, and my voltage increased around .4 volts, while running engine :)

[@landcare-outdoorfun176]

Thank you for sharing this video. I appreciate all of your hard work and time, in making these videos.

[@paulgraham6353]

Thank You. Perfect. I like the no nonsense presentation too. No hand waving, no attempt to make buddies, no guitar overlay, no trying to show off or act cute.

[@kowhort]

Excellent video, very informative!!

[@judyfowler9750]

Eric you are very thorough thank you

[@knownoversight]

Thanks so much, I had a flat battery this morning, changed it but was still worried about the alternator, but thanks to your video I've just tested it and found it to be absolutely fine! :)

[@lisnut]

My sons Exterra had a battery light on, with the car started was only getting 12.4 volts felt the terminals was very hot ! Turns out he just replaced the battery but had a loose connection! after cleaning and tightening it was charging at 14.3 v Thank you So much Eric I always tend to watch your Video's, Good content with out allot of fluff!

[@stephenkuper9549]

Hey Eric great video. Maybe i missed it but I only seen you do a resistance test on the the neg side but not on the pos side . You did mention where to test on the pos side do you use the same limits/scale on the pos side .1 to .2 volts resistance?

[@NathanReevesnate808]

Yes one probe goes to +b on alternator

[@TEAMCREAM_96]

I would never take my car to a mechanic unless it's something I really couldn't do like transmission band adjustments or getting an alignment done. It just feels wrong to have someone else touch my car with out me being part of it

[@koollee]

Lol.. I hear u. i often feel the same

[@TEAMCREAM_96]

@Edie Beacon look it up smart guy

[@stevebrown8233]

Hi Eric, Saw your video and have now sorted my voltage problem, great vid and thanks, Steve from Exeter in Devon, England.....

[@geezerhull]

Thanks for the excellent video Eric. It was very helpful. Mine turned out to be the fuseable link near the pos battery connection. It was fried. Am assuming that one of it's functions was to provide exciter voltage to the alternator. Also great to find out that the ecm could be controlling the alternator and that it can be bypassed in a pinch.

[@mrbreezeet1]

please note also, and yeas ago, we chased this problem for a few days. another thing to be aware of, is when you turn your key to the run position, the batter light should light up. if the battery light is burned out, it will not trigger the Alternator (Voltage Regulator) to begin charging. In the case f the vehicle we were chasing the problem on, My Boss, was "exciting" the Alternator At the field tab on the Alternator, And the car would begin to charge just fine till the car was shut off. Shut the car, start it again, Not Charging! Excite the Field, System charging until Car was shut off. WTH? This was in the days before internet, So I went home and did a bunch f reading (from real books.....LOL). It never really said "Hey, if the battery light is burned out, the car won't charge" I had to "read between the lines" Went in next day, replaced Alternator/Battery light in the dash, Car started, and began to charge.

[@tomtroszak]

Outstanding comment, Thanks!

[@maingun07]

For diesel owners: If after starting the voltage is near or below battery voltage, the glow plugs may still be on. Glow plugs draw a lot of power and in some systems may be still be on for a minute or two after the engine is started. Either wait until the glow plugs shut off or disconnect the glow plug relay prior to starting.

[@austinburke9718]

Thanks for videos. They have helped me when working on son's 98 4runner. I had an issue that seemed intermittent but was certain it was an alternator problem. Issue happened a couple of times again after checking all connections. First time testing alternator all tests passed. Performed again a few days later with diff test set and found diode test was failing. So, I got a rebuilt alternator from X part store. While testing in evening with lights on (eight miles after installing the alternator), radio and lights blinked. It blew the low beams. I installed the old alternator in parking lot so that I could get it home. I didnt want to take a chance on blowing high beams while trying to get home on new alternator. Took the new alternator to X where they tested new alternator - tested fine. It did not blow any fuses so I determined that it was not a high current issue but high voltage issue. X gave me another alternator and have had no problems. I still think it was a regulator issue with the 1st rebuilt alternator. Thoughts on supporting my theory. X would not replace my bulbs because of their alternator tests. Not happy because these bulbs are $25 for each. Thanks SteveBurke

[@TheGtech83]

Your video is still providing support, Thanks Eric!!!!

[@notasfancy]

Hahaha man. you look like Geroge Clooney. thanks for the tips brother. great job!

[@jesserigs2647]

You had me at "stay dirty"

[@user-ui9df3vw1v]

I love the way you simply explain it clearly...Great ..Wish you where here.And .I could bring my cars to you..Profasional man.

[@judyfowler9750]

Super great info much appreciated. I changed my terminals hoping it was it as the old ones were old N a tad corroded. The weather has been really cold after it started with a jump I failed to start for a few days so it was drained.

[@stevenbear218]

I just had a check charging system and my battery light came wasn't too sure what to do thank you for making this video very helpful 😊

[@4malulz104]

I went through all these tests because I couldn't find a parasitic draw. The truck sitting still and off was drawing about .84 amps with the key off. I pulled all the fuses one at a time, and didn't see an amp drop on any of them. When I checked from the battery to the alt casing, I got the .84 amps again. After checking and cleaning all my connections, I still have the .84 amp draw condition. But the alternator passed all the tests. Does this point to a bad diode within the alternator? The only other part I haven't checked is what appears to be a fuseable link in line from the alt running back to the dist. area. The truck runs and seems to charge the battery fine, but when it sits for more than a day, the battery is dead. Would this be caused by a bad diode? OR, should I go the extra mile and check my connections at the starter as well?

[@Dee-hi5zj]

Interesting that in no comments asking for add'l info does Eric ever reply here... (Maybe on his web site) so all you'll get is other opinions from other people who also don't know how to fix similar problems... GRRRR...

[@steadyeddie7453]

You did a good job stressing the need to check connections. I'll take it a step further and say that when I have electrical issues I start by disconnecting the battery cables and cleaning the posts and terminals. Especially those side post batteries. They can hide corrosion at their connections. And unfortunately a voltage drop test won't show bad battery connections. Cheers.

[@obsessionsmotorcyclecardet15]

George Clooney lol . I have only just found your channel, I have to thank you for taking the time to do so , I've just watched your battery drain video and im having the same problems with my KTM. I've found out I have a 5.5amp drain and pulled the fuse out of the solinoid and it goes to 0.00 so now at least I have some awnsers. Man I love you.! I fear my alternator has also gone .so here I am .

[@waynep343]

working on cars.. voltage drop testing do you have a digital voltmeter..set it to 20 volts DC. engine off.. headlights on for one minute. then turned off.. check battery voltage.. 12.65 is a fully charged battery. 12.45 is a 3/4 charged battery. 12.25 is a 1/2 charged battery. if you have less than 12.5 volts have your battery charged and load tested.. once you verify that the battery is close to a full charge after you have removed the surface charge with the headlights on trick... get the engine started... turn the headlights back on.. Negative battery post to the positive battery post.. 14.1 to 14.8 volts is expected.. Negative battery post to the engine block. 0.04 volts DC MAX.. Negative battery post to the body of the car.. 0.02 volts DC MAX. Engine block to the Body.. 0.02 volts DC. if you get more than the 0.04 or 0.02 volts on tests 2, 3 or 4.. you have a bad ground connection.. you can and should also.. after running the voltage drop test above.. test from the battery post to the alternator output terminal.. because of the amount of output.. i normally expect this to be up around 0.07 volts..

[@123xmilanx]

If u do have a bad ground connection how do u fix it? I have a honda civic 2015 and I just replaced the alternator and the battery and the cars battery connection light came up

[@tuggers7]

i love that little motto of yours....."stay dirty"......

[@danemontague6760]

hey my battery does not charge..got the alternator checked..no problems there..what else can i check ?

[@anfihn]

Dane Montague Uh, the battery.

[@maurice9118]

Dane Montague Jup take a multimeter and start checking it

[@azmibeyrouti9632]

thanks man this video was so helpful for me its the 2nd time that i changed my altinator within 3 months i will check the altinator connection cuz i have doubt about it thanks again Mr.Eric

[@padraiggalvin2807]

Great video. It refreshes the small things a person may not think of. I hate those new smart charge systems where the charging is controlled by the ecu

[@FxScalper]

Manufactures do not make adequate ground for alternators. That is the problem. If they did, they would last longer and have more stable voltage. Bolting a alt to engine is NOT enough ground. Grounding alt body to chassis is better but still not enough. The only way to properly ground a alt to work optimally is to take apart alt and modify casing so that you can secure a 4gauge wire to the B- (negative side) of the rectifier bridge directly to the battery ground post. Do this and no more voltage/amp drops (assuming everything else is good).

[@paulchamberlin5354]

Great thing about my 2006 Pontiac pursuit gt sedan... it tells you on the cluster when the alternator fails. 😊

[@phantomwalker8251]

so does my 1960 f100,but,non,tell you when the leads are corroded..which,is the main cause of dead car.lights,ect.

[@oneromevad7853]

This guy paved the way! Bravo Eric The Car Guy!

[@anthonyjones5334]

Bbb industries is my goto for ALL my wiring diagrams and tsb info ! Thank you guys for that info and to eric for your guidance on many things!!!

[@cward1954]

They don't do those anymore.

[@anthonyjones5334]

@@cward1954 yeah I recently found that out its a bummer cause I loved that site. I wish they would give reasons why or where 1 can go to find them

[@GibsonGarage]

My voltage needle bounces when I turn on my headlights I did the drop-down test and it seems fine, any ideas?

[@glasser2819]

replace your Serpentine tensioner + belt if above 80kMi

[@thomaseaster5442]

Check your ground on the small wire on the batt

[@alnomatt]

IF you START the video at 10:45 and end at 10:54 it appears as if the draw goes to .02 then .03 and you said that for this test it only registered .01. My question is not as a criticism but is it okay if instead it reading .01 it does read .03 would that be a unfavorable outcome? Perhaps you didn't notice the reading or it is not relevant? I'm just curious. Seems to contradict what you stated before.

[@mandom4486]

.01 - .03 is completely different from what he meant which is .1 and above which means there's too much resistance on a wire... It can be a corroded or rusty ground/connection on battery or a slit on a wire/broken insulation causing not all the power to get to its destination like say battery ground terminal to the ground on the chassis/engine block

[@MCraig-ly1qq]

Yes 0.03 is great. He said the limit was 0.10 Volts not 0.01 Volts. A reading of 0.03 is one third of the limit. You're good to go.

[@mikebarnes3238]

Oldie but a good one. Nine years is a long time and you only got better

[@zanosshade7903]

man the connection issue is no joke! just went through two days of hell and may have killed another battery before i found a loose ground wire on the alternator. tightened all my connections last night. car started right up this morning. THANK YOU

[@nitecorepd2230]

never do the alternator test by removing negative cable on newer cars!!! or u will fuck something up. That shit worked fine with older cars but not today!

[@keysersoze3777]

Your video covers everything. Great! I like do work in my 2004 Sierra SLE ext. cab 5.3L V8. I just got a new battery and now in the cold morning when starting the truck a warning sign comes up, "Battery not charging" and voltage drops to 9V this lasts for 20min till engine warms up, then voltage goes up to 14V. Is that a sign a have a bad alternator? Thanks!

[@tinazizzo5733]

Edson Colle

[@justingarcia8272]

My 02 Sierra has been doing the same thing. Was yours the alternator?

[@jodysaxon9258]

Hey Eric I totally appreciate your video I usually have to watch five or six other videos just to gain the knowledge I gained from your one video keep up the good work man I will save like and follow your channel thank you.

[@brucewayne-cave]

Best video I have seen on this topic. My 2004 Expedition "Check Charging System" randomly beeps, when it rains. Then went crazy beeping for 4 hours on my last trip in the rain. So we had to turn the radio up to full, for our sanity. The next day no rain, no beeping. New battery, alternator tested fine. I suspect a wiring harness?

[@HennessyLane1]

can you do a video on overcharging my 2007 ford five hundred randomly puts out 19.5v

[@adelemartinez8235]

That's what mine is doing. I've blown thru 2 brand new batteries and 2 regulators, in the same day! I have a 1990 Ford van. With a 5.8 liter engine. Someone told me today that I should sell it for parts. So frustrating.

[@johnmurner2418]

@@adelemartinez8235 have you fixed it?

[@johnmurner2418]

@@adelemartinez8235 have you fixed it?

[@johnmurner2418]

Have you fixed it?

[@adelemartinez8235]

@@johnmurner2418 no. I haven't. It sits outside still.

[@michaelrodgers41]

u get any sleep man..take a vacation. u very infoemative. thanks.

[@rjserra5535]

Thanks Eric. I appreciate the information and training. It is very useful.

[@COOLESTDELLCAIN]

My car won't start at all. The last time I got it started I noticed that the alternator wire was smoking. I believe this is the reason that my battery died. What can I do about this and could you give me a reason as to why this might be happening?

[@hadath09]

Hi Dell M, I have the same exact problem. Did you figure out what went wrong? Thanks. [e-mail].

[@AlabamaTree]

I've got an old Mercedes truck with the voltage regulator on the back of it. Sometimes it's charging at 14.4 14.8 volts and then it's goes crazy and shoots up to 17.8 volts. Then it's goes back to normal. Is this likely to be more of an alternator problem than a regulator problem?

[@HennessyLane1]

AlabamaTree my ford five hundred shoots up to 19.5v into i take a cable off the battery restting the PCM

[@dustinjohnson1952]

Check battery connections battery acts as a capacitor and stabilizes the alternator output

[@christinashoffner6973]

ok K I zssssexwde1qwddw1 f t TV tecrwe3cerdrdrd3ffr3fffefeffcecferdr3d3erccrecr3cf rcecf3crf3ercceecffdc3rce carat my mom

[@sinewaves5806]

I love you EricTheCarGuy! Your information has saved my bum plenty of times. I wish there were a way that I can ask you more direct questions. I am trying to diagnose my brothers 99' honda civic LX's electrical problems. I suspect that it is the Alternator, but I want to test everything else possible first.

[@mstrehle42]

I have to say what a Great video walking thru voltage drops and how to go threw a proper charging system and how to rule out other areas. I have a 2007 Dodge Ram 2500 5.7 L Hemi I have replaced the ECM Module and Starter a year ago. My Mechanic had my truck for a week he does a great job but I work for myself and dont alway have the money. I am having the same issue i had a year ago, I was coming home from a job and notice the battery discharging negatively and it got worse as the day went my alternator had a bearing hum replaced it and still having issues ALternator was not the issue but the bearing was showing wear. I know alot about motors and engines but I dont know everything Im a utility engineer and Im knowledgeable. This Video Made my battery and ECm and charging system easy to understand . Thank you for the Education......

[@TOPBOY52959]

And this is how i learned that my alternator is a POS

[@cobretticobra7911]

Hey Eric My alternator is making a rattling noise that seems to be in sync with flickering lights on the dash and head lamps just noticed the problem on my way home from work any ideas (2000) gmc 6 cylinder

[@owentheboi9368]

Smith Weson my 2002 MK triton is doing the same thing, don't know what the problem is. Did you diagnose the problem?

[@markmarchand8376]

You are awesome....You along with Dan Sullivan and the Adept Ape guy are really good. Thank you Eric.

[@eyeprod3101]

I like your straight forward approach. Thanks for the vid. It helped me.

[@acoow]

9:43 What happened to the positive side check?

[@hannguyen-ny3du]

should be same idea, pretty simple. positive side on alt to positive terminal.

[@acoow]

han nguyen Thanks, Han, but I would not guess with something like this. It would be a shame to fry an alternator doing the check the wrong way.

[@BassheadGTP]

acoow When doing the test on the positive side you touch the pos lead of DMM to pos on alt and neg lead to pos on battery, this will not hurt anything. in a nice DMM if something goes wrong theres a circuit breaker inside of DMM that will break before damage to car occurs. Im a certified diesel tech.

[@blueyedhusky]

BassheadGTP Is this with the car running also? Can it be done with the car engine off, or even with the alternator disconnected? I mean, testing between the battery's positive terminal and the alternator's connector. I ask because it's impossible to get at the alternator's connector when it's mounted.

[@SamnissArandeen]

5:00 You would not believe the amount of alternators I've fixed simply by checking the belt tension.

[@Ultrajamz]

Samniss Arandeen if I am suspecting the alternator belt tension, (odd squeek at low RPM range and intermittent rough idle) could hooking up a 2nd battery (as if I were going to jump it, even though the car starts and runs), diagnose an alternator issue? If I connect a 2nd battery, it could smooth out the voltages, and if my idle issue goes away, then I know its power related?

[@Ultrajamz]

Samniss Arandeen if I am suspecting the alternator belt tension, (odd squeek at low RPM range and intermittent rough idle) could hooking up a 2nd battery (as if I were going to jump it, even though the car starts and runs), diagnose an alternator issue? If I connect a 2nd battery, it could smooth out the voltages, and if my idle issue goes away, then I know its power related?

[@SamnissArandeen]

Ultrajamz I've never done that particular test. Usually I just check belt tension during the visual check of the alternator itself.

[@bblando65]

+Samniss Arandeen you wouldn't believe how many people falsely believe that by tightening their alternator belt, they'll fix an alternator problem...all they usually do is overtighten the belt, and burn out the alternator bearings..so yeah, 99.9999% of the time it is not belt tension...

[@georgiachase9258]

can an alternator still be bad if you pull out the cable and it runs the positive cable

[@SeaRay45DB]

This was a great video. I was going to replace my alternator, but now learning that you want to be .5 above the battery condition has me thinking twice. I have done a peristaltic test, I do have an isolator in my truck, same batteries, Interstate, same age. Took the truck to Good year, they ran the test, everything came up clean, but still battery dies after 3/4 days.

[@shirleycrane8001]

Thank you Earic , you have been so very helpful . I will let you know the outcome of my finding.

[@chad61610]

What about testing for voltage drop on the positive side of the system? I know you mentioned it but didn't show how to go about it. Did I miss it?

[@mikebishop2406]

Exactly. I thought I missed it too. No. I triple checked it. He did not show it.

[@mikebishop2406]

Image result for voltage drop test on positive battery cable Connect the meter positive lead to the clamp on the positive battery cable, and the meter negative lead to the end of the cable at the starter. Crank the engine and note the voltage reading. A good cable should have a voltage drop of 0.2 volts or less. Voltage Drop Testing - AA1Car This is what I found.