Alternator not charging battery

Removed Alternator on 2016 4Runner, had it tested, ok, reinstalled it still not charging. I have checked all fuses, under hood as well as under leftside of dash. Double checked all 7.5 fuses. Any suggestions?

 

Factory battery?

If it is its 8 years old.

 

Well if it's not the alternator its the battery. And if your getting voltage its not the fuse.

When did u change the battery last? What kind of battery?

 

New Battery installed first. Removed alternator,had it tested for output; 14.2 volts.

 

Brand name of battery is DieHard Gold. 750cca.

 

If your alternator is putting out 14.2V its probably not that.

By not charging what do you mean? Battery dies quickly? You probably have excessive current draw when its not running.

 

Hmm, well it's not an AGM. Alternator tests fine and new battery.

If you had it tested off the car you could still very well have a charging system problem. damaged battery cable, either positive or ground side either one, a bad loose or corroded battery cable connection, a bad or loose battery ground. Could also be a terrible parasitic draw.

 

Charged up battery to full charge. Current state of charge of battery 12.8 volts . Started vehicle checked charging voltage at battery posts: 12.2. Headlamps on,blower motor cranked up to full load, battery voltage drops to 11.2.

 

Also, before starting motor and after fully charged battery was reinstalled, checked for battery light in the instrument cluster . There is no illumination. I do know that if you do not have the battery light does not light up the alternator voltage regulator does not get energized to allow alternator out put.

 

Is there a hidden fuse somewhere I could check? I did add 12 volts to the alternator wiring harness 4 pin plug. The battery light in the instrument cluster illuminated.

 

I checked all underwood fuses and under dash at leftside. No blown fuses. Battery cables clean and tite. No corrosion at alternator post. Main alternator fuse good.

 

Check grounds

 

Checked all body grounds,engine to frame grounds, main negative cable as well.

 

Tested ok but still not charging. then it's the alternator. How many miles on your 2016? If over 140K, that's probably it.

 

The vehicle has 78k on it. My customer bought it brand new. The alternator is oem. My experience is that most alternators usually last about 100 to 150k. But Asian vehicles have a pretty good track record of manufacturing reliable electrical components. If this tested alternator doesn't charge I will replace it with a Nippendenso alternator. I've never had a issue with them.

 

Was gonna ask mileage. Alternator brushes go between 150-200k miles typically.

 

I'm fighting a parasitic issue with my AGM battery (Odyssey 34R PC1500), supposed to be a super battery. I have now understood that with having so many lights and gadgets drawing power, perhaps the alternator doesn't have the best chance to charge the battery. My issues are that when I don't use the 4R for two weeks, the battery is just dead. I have taken the 4R to Autozone and O'Really's and in both tests they are showing that the alternator is going bad. The battery is charging a little bit, it is around 52% after using the vehicle for a week.

I ran into this interesting video and gadget - seems like it makes sense. Has anyone used this voltage booster? Seems like a fancy simple circuit, but makes sense from the videos. Anyone here have done this one?
https://youtu.be/F69vEuy3wDs

 

ChessGuy, how many miles on the alternator? I ask because brushes need replaced somewhere around 150k - 200k miles.

If it's just going dead while sitting, it may be a parasitic drain, but you have to use an ammeter to know. If you have aftermarket electrics on the vehicle, you can try just disconnecting them all and see if the problem goes away, but the ammeter will be faster/better. I had a remote start fail on a Corolla once, and the first sign was the battery going dead when it sat for a few days. Turned out there was a parasitic draw of about 350mA that went away when I pulled the two fuses for that. IMO, it's unlikely that the alternator is 'going bad'. More likely, if you have a lot of electrics, that the demand is more than the alternator provides.

 

60K on the entire vehicle and on the OEM alternator. Which to me still is new, but, but....I got so many damn things on this 4R, it ain't funny anymore. It looks like a xmas tree at night. Seriously, I got too much crap drawing on it, compressor, light bars, cameras, radios, you name it. I upgraded to an Odyssey battery when I started adding all the other electrical crap and the battery just dies if I don't use the vehicle. It is almost on the clock, if I leave alone for two weeks it is a guarantee that the battery is dead. And jumping this with the Noco is getting old and so I'm trying to get to the root of the problem. I am not sure that the machines at Autozone can really diagnosed well the alternator but in two different tests, they showed the alternator is going bad. The battery is ok at 14V, and state of charge is 50% and going up......so trying to figure out here. That's why this video and explanation on AGM batteries (more V) and the OEM alternator don't seem to work well and the little switch pushes the alternator to charge the AGM battery.

 

Gotta check for parasitic draw as your next step. Do you have a voltmeter and know how to use it to check amps?

 

The voltage booster is common and required for AGM, although some will say you don’t need it. The specs on AGM will state what voltage is required to charge from an alternator and you can measure yours and you will see it needs to be about 0.5V higher. Just do it.

Some parasitic draw is normal but you may have a problem. I found trying to measure with a clamp amp meter was difficult and the vehicle takes a while to settle and I get different values.