Causes and Fixes Battery Light On but Alternator is Charging

The reasons why a charging system light can come on when the alternator test good and is charging. For More Information Read Here: www.backyardmechanic.org/caus...
Possible Causes
Alternator Low Voltage Output or Intermittent Issue
Bad Voltage Regulator
Bad Battery Sensor
Bad Battery
Bad Wiring Connections
High Amp Load
Blown Fuse
Warning Light Malfunction or Wiring to the Indicator Light.
Bad PCM/ECM
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[@Remodelsbyleo]

Great video! Thanks! Sometimes brushes can wear inside alternator and not make good contact. Also, for some custom set ups, you can upgrade to an adjustable regulator on alternator to fine tune the voltage. Just for general knowledge

[@auginater4200]

Great video thanks I'm working on my 06 Cadillac STS v8. It's very interesting what you said about checking the alternator's voltage is in the proper range, and how it might be a good alternator but your battery is bad

[@danpicocfp6276]

Great technical and educational rundown. Keep good going!

[@DANIELROMERO-cv3tu]

Great video I’m checking everything you mentioned. Batteries are 2 yrs old had them checked and👍🏼. Alternator next. However a mechanic that works on emergency vehicles told me to swap the batteries around every 3 months. So the primary battery gets changed. My truck has two batteries. It’s a 7.3L diesel.

[@davidhartley1108]

Great video. Covered all bases.

[@samuelberry4311]

2003 Toyota RAV4 battery light is just haunting me!! Check and cleaned my connections and wires. Got done watching your video and now I’m ready for round two on checking other components. Much respect 🫡

[@eyeheartsushi2212]

Did you ever figure it out?

[@samuelberry4311]

I had that RAV4 checked out by multiple shops and couldn’t find the issue, so I solved the issue and sold that bad boy😁😁😁

[@jacquesprovost5062]

Thank you for the information. You're the first guy that talks about the onboard computer. My voltage is sometimes 13.2 V , In which case my battery light lights up also as much as 17 V. In which case the battery light lights up. Change the battery and change the alternator but not original from dealer. It's a 2006 Lexus R. X330. What I needed to know was Yoon board computer sends a signal to the battery light on the - because it's not reading the proper voltage coming out of the alternator that makes sense to me now.

[@timduncan2531]

great video covered all basis.

[@HalifaxHercules]

I had a Charging System Malfunction warning recently with my 2016 Mazda CX-3 AWD. Turns out that it wasn't the battery or alternator that was a problem, it was a faulty serpentine belt, which was a big relief as I only had to spend less than $150 on repairs.

[@michaelvesel5275]

I have an issue with the multifunction switch , my withers sometimes won't shut off , it seems like when I use the van more and it heats up inside ,it gets better and the wipers quit

[@silverheartandsoul]

Good video, Thank You!

[@user-yi6td6fu2g]

my alternator bracket broke and i have the part on the way but i connected it directly i put a little supe glue on the just so it wouldnt move not mess with the prongs, ive got the warning light brake and battery. i checked the fuses the connection im hoping once i fix the bracket the warning light will go.

[@joavanpuran3495]

Bro. I have a 10th gen civic. 2L non turbo. Oil and battery light came on and car loss acelleration.It cleared after restarting the car. What’s your take?

[@AutumnBassett-fq5ef]

I watched your video. I'm curious on your opinion on this. I've replaced my alternator and throttle sensor. Ever since then my check charging system keeps coming on but my vehicle seems to run fine. I've made sure there's no corrosion to the battery. I don't know what to do. Frustrated. Please help

[@drewdavis239]

Bmw e39' s. Bmw e46's they are linked to the low oil light sensor. If the oil sensor in the oil pan is a open circut, will cause this issue.

[@reefreef7379]

Could you please elaborate this further ? I’m using E46 & have the intermittent battery light warning

[@Cedarrob216]

Dude. THANK YOU

[@ibrocpcanman5342]

You missed one more thing on your list! ELD (Electronic Load Detector) and its located inside the fuse box UNDER the hood...

[@rexdrax4649]

do you know how to fix battery light

[@sgsuper1150]

I have a voltage drop under acceleration to 12.3 volts unless i put lights on and it stays at 13.7 with a new alternator and rectifier

[@ronniepemberton1942]

I have an 08 grand Marquis, battery light comes on intermittently, checked voltage when light is on, reads 14.3. also reads the same when light is off. Any suggestions?

[@abdulhassan1107]

Same here, 2002 LTC but only happened after rebuilding the alternator using new bearings, new rectifier and the same old voltage regulator. I'll replacing the VR and see what happens. The charging is fine, 14.4V no lights flickering, window regulator is quick etc checked each and every fuse, fusable link.. all good. Will let you know after i change the VR.

[@bernardocisneros4402]

@ronniepemberton1942 There's a wire that goes from the ignition switch to the battery light then from the battery light to the alternator. This wire grounds out at times within or near the voltage regulator. When it grounds out is when the battery light comes on. Most of the time it's inside or near the voltage regulator where it grounds out, but it could be that this wire's insulation has been damaged and it's grounding out between the battery light and the alternator. You first need to make sure the wire from the battery light to the alternator isn't shorting out. Then you can either replace the alternator or disassembe your current alternator and replace the voltage regulator.

[@ronniepemberton1942]

Thanks, I replaced the alternator 3 prong wiring connector and problem solved.

[@bernardocisneros4402]

@@ronniepemberton1942 Good to hear. So that's where it was grounding out? Thanks for the update.

[@9medrano6]

My battery light is on, I changed my ignition coils and spark plugs the other day, and now the battery symbol comes on, and sometimes the wrench symbol comes on

[@darrellwoods5961]

Got a 2002 Nissan Frontier replaced alternator and Battery and cleaned up Battery Terminals etc. Tested Voltage with Everything On. Ac max, Headlight high beam on etc. 14.3 voltage at idle. Lights On still.! SMH help please

[@HVAC_Mechanic]

You checked all the most common causes, so the issue is likely harder to troubleshoot. The computer or the wiring may be having a problem which is more difficult. I would double check all the connections, check for any damaged wires, and be sure the fuses are all good.

[@GereDJ2]

See Update below: I have a 1990 Toyota pickup with intermittent alternator light coming on. Cigarette lighter has a volt indicator plugged into it which reads about 11volts when Batt light is on and about 13-14 volts when the Batt light goes off. Sometimes when I firmly tap the alternator with engine running, the Batt light will go off, but not always. I think perhaps the voltage regulator or maybe the brushes in the Alt are malfunctioning? Hard to say. Comments? Update: It was the brushes. They had worn down to the very last section of contact material and tapping the alternator would momentarily make contact with the commutator and charge and dash light would go out. I replaced the alternator and inspected the defective one before returning it as a core and the commutator had two, 2-3 mm grooves in the stator and would have needed to be turned smooth, so the most expedient action was alternator replacement for about $140.

[@HVAC_Mechanic]

I would take the alternator to an auto part store and have them test it. If it tests good, then I would replace the voltage regulator.

[@bernardocisneros4402]

That is very smart of you to use a voltage indicator plugged into the cigarette lighter. The voltage indicator helps eliminate the diode trio and the accidental grounding of the wire connected to the battery light in the instrument panel. It's either going to be your voltage regulator, rotor, or the stator windings. If it were the brushes, the light would go off every time you firmly tapped the alternator. Let us know what fixed it. I'm sure it will help someone else in the future.

[@GereDJ2]

You were incorrect on all counts. It was the brushes. They had worn down to the very last section of contact material and tapping the alternator would momentarily make contact with the commutator and charge and dash light would go out. I replaced the alternator and inspected the defective one before returning it as a core and the commutator had two, 2-3 mm grooves in the stator and would have needed to be turned smooth, so the most expedient action was alternator replacement for about $140.

[@bernardocisneros4402]

​​@@GereDJ2Thanks for the update. Goes to show how much I know...lol, but that voltage indicator is a smart move. It helps you eliminate some things. The majority of older alternators from the early 90s and back grounded the battery light through the brushes and that's another reason I didn't think it was the brushes. The newer ones get grounded through a resistor before the regulator and brushes. You most likely had the newer style, but I could be wrong again. Thanks again for the update.

[@motologist1917]

brother i have ford fiesta 1.4 tdci my problem is that whenever i start the car battery warning light comes on the dash but if i fully press the throttle all the way to 5k rpm it starts charging and light goes offf , plz help me to solve this issue

[@HVAC_Mechanic]

I would test the battery and the alternator.

[@motologist1917]

@@HVAC_Mechanic battery is new as well as tested

[@monicamccloud6261]

My battery light goes on and off like it lose power but I had the battery and alternator tested but they said it was good Please help me

[@HVAC_Mechanic]

Check the battery terminals and all the other connections at the alternator. If the engine is running good, then there likely is a loose connection.

[@gordoncolbert4582]

Hooked battery up backwards now windows don't work, radio doesn't work and the battery light is on. Any suggestions

[@RTJ3DCosplay]

backwards... uve blown fuses is my first guess

[@rugdoc97]

Your fuse behind your battery blew gotta replace it i just had that happen when someone hooked it up backwards

[@PrudenciaRuiz-lt3uo]

Thx

[@michaelgarcia1251]

Well Dame

[@amariilu6516]

Humming sound under hood when trying to start, clicking noise when trying to start.. the starter is less then a year old timing belt changed - battery less then a year old. I’m sick of it

[@bernardocisneros4402]

It's most likely going to be your battery, alternator, too much resistance in thick positive cable or thin positive wire going to starter, or bad ground from engine block back to battery. If your battery terminals are dirty, clean them. Make sure all the connections from the battery to the starter are tight; this includes your battery terminals.

[@ZEBBOSS7]

What

[@annettenorris412]

🙏🏿🙏🏿🙏🏿✌🏾✌🏾✌🏾

[@VaughnTaylor31]

I hope you see this. I recently had my alternator changed a few months ago and just a few days ago I had to replace my battery. Now since I’ve changed the battery the comes on the car drove for a few days and gave out. Took the battery in they said bad it was a bad battery I was able to exchange it. However I put the newer battery in and the light keeps coming on but now the car won’t keep power I was able to drive it just a little before it gave out on me again. Any suggestions . PLEASE I NEED HELP

[@HVAC_Mechanic]

I would double check the battery terminals are connected good and test the alternator.

[@VaughnTaylor31]

@@HVAC_Mechanic THANK YOU!!!!

[@lillianm1242]

@@VaughnTaylor31did you ever figure out the issue I’m having the same problem can’t figure it out. Tia

[@VaughnTaylor31]

@@lillianm1242 I didn’t. I just purchased another alternator so hopefully in the this coming week I can get it put on and or figured out. I can give an update when I get it done.

[@Daplaayaa]

@@VaughnTaylor31hello i have the samr problem did it get fixed? If you did what was the problem

[@shreekrishnaenterprise7756]

My car ford fiesta 🚗 this problem friend

[@rokas321211]

Did you fixed?

[@motologist1917]

wt was the problem

[@PrudenciaRuiz-lt3uo]

2002 Cadillac town car

[@PrudenciaRuiz-lt3uo]

Need a code car won't start

[@jaymemccall1665]

Battery don't discarge