NEW BATTERY AND ALTERNATOR STILL NOT CHARGING HELP!

I'm thinking alt or 3 pin connector/wiring. The alt should have 14v on the post when truck is running. Also, power goes from alt post into the fuse box to the 80a alt fuse then back out to the battery. I've seen on this forum someone had a loose nut on that post inside the fuse box. That's the white charge wire coming off of the alt post. If you don't have 14 on the alt post itself there's obviously an issue. If you continue to drive like this you're literally running off battery power only. Only a matter of time before the system gets so low that they start shutting off as you're driving. First the radio then you'll have poor throttle response (tps) shit like that. Multi-meter is your friend. The 3 pins from the alt connector go to a 4 pin connector right under the fuse box. Unplug both connectors and check for continuity. The 4th pin in the 4 pin connector under the fuse box is the starter signal wire that goes down to the starter solenoid.

 

Just curious what Autozone said the voltage output was measuring only the alternator without the wires. Or did they just say it's "good"? As others have said, sounds like the wiring as voltage should be ~12.6 V or greater when the truck is NOT running and ~13.8 V or greater when running with all accessories off (Alternator output).

 

I did suggest battery positive to Alternator case Never saw a reply!!

 

if you apply +12 to the case of the alternator you're gonna get a nice light show, and then let the magic smoke out of a bunch of shit. Maybe that's why we never heard back from the OP, a moment of silence for the fallen please...

 

Regardless, you TW folks have a fine way with words to get me smiling and chuckling

 

Funny How do you read voltage please tell me??

I was taught positive to ground .


If your alternator is shorted to the case you have a problem all ready and it would have failed the first time at Auto Zone.

 

You just quoted a guy talking about a ground with I suggested that too, battery positive to case???? What are you talking about?! First of all, the alt is grounded by being bolted to the block, secondly, you should NOT have wire going from ALT post straight to battery. The charge goes from alt straight into the fuse box to the 80a ALT fuse this is also known as fuseable link. Then from 80a alt post it goes back out to the positive of the battery and that's how the charge system works period. If you have a wire going straight from alt to battery your shit is NOT factory. Just FYI DOG!

 

I think it's more about people not knowing how to read and write... So they have this response in their head but they can't translate it to the computer screen. Then when you read their response it's even more confusing as to what they're trying to say...

 

With a multi-meter... your answers scare me bro.

 

Op is at work rn but we were on the phone trying to figure it out last night. He replaced the positive terminal, and tested voltage at alternator stud. Same 12.6v. At this point we are thinking it is probably the 3 pin plug as someone here pointed out. He tried to clean the connector with no success and he said one of the terminals had 12v with ignition on but I forgot which one when he gets home we can test it further. He also had a few dash bulbs burn out last month and someone said that if the charge bulb is burnt out the alternator won’t get a signal to kick in so that’s a possibility too. Thanks for everyone helping out so far! If nothing else I will probably drive out there to help at the end of this month. He lives in AZ and I’m in CA.

 

I represent... Er resent, that comment
That feeling you're describing is all too familiar

 

BTW the ecu tells the alt what voltage to put out so if one or more of the 3 signal wires to the alt does NOT have continuity then it's more than likely going to be a wiring issue. The alt is grounded by being bolted to the block so no worries there. If you have continuity on all three wires and the connector is fully plugged in, I would lean towards alt itself. You need to use a multi-meter to determine this. So you're not chasing your tail. I recently re-did my entire charging harness for unrelated issue (starter signal wire) and after I put the new harness in the alt was only putting out 12.8... Upon inspection, one of the 3 wires on the alt connector had broken. I de-pinned the broken wire and re-soldered the wire to the pin. Re-pinned the connector and boom back to 14v. Don't chase your tail by jumping critical and easy diagnostic steps. Other cool thing is, you learn things with experience. Now you'll know more for the future.

 

I still think you should study the link I posted in post #17.
Get a good understanding of how the charging system works.
Then get a wiring diagram for a 2000 Tacoma (I don’t have one for a 2000)
See what pins on the connector go to what (IG, S, and L)
Test the connections and go from there.

Again, if you study the link I provided earlier, and can get a wire diagram.
I really think you can have this figured out.

 

Very wise advice. Couldn't have stated it better.

 

You guys need to check for CONTINUITY. Not voltage. I mean yea, make sure you know what the voltage is at first but that is only going to tell you there is a problem. Continuity checks for resistance in the circuit or an open. I'm betting an open. The ecu controls output. It needs information to decide output. The only other thing is alternator itself but that would throw a charge light on dash. Now if said charge light is not lighting up because OP's lights are burnt out, you're now chasing your tail. If the charge light is on on the dash it's pry the alternator itself. I guess that's why having working warning lights help...

 

I really think they only need to back trace to the AE1 4 pin connector right under the fuse box. That's the junction where the 3 wires from alt connector go to. From there they go into the fuse panel.

 

Take multi-meter, put it on OHMS 20. Now unplug ALT connector. Now unplug the AE1 4 pin connector right under the fuse box. Now make contact on one of the pins on the 3 pin ALT connector while simultaneously making contact on one of the pins from the AE1 4 pin connector. If the screen doesn't change move on to another one of the 4 pins. Do this until you find continuity on one of the circuit. The screen on the multi-meter will change and display numbers until they slowly come down to either 0.00 or 0.01 0.02 something like that. That means continuity. Meaning, your wire is not broken, electric has a good path. Do this for all three pins. So in review, between the alt connector and the AE1 4 pin connector under the fuse box you should have continuity on all 3 wires. That's the entire charging circuit. That's it. Positive connection between alt and battery is NEVER suggested although if you search big 3 you see people doing it all the time. That's why there is an 80a alt fuse in the fuse box. Charge power always goes through this fuse first, then to the battery, Never directly from alt to battery.

 

Is OP in Phoenix?

 

Now that I re-read this it sounds like the previous owner was having a charge problem and threw a new alternator at it thinking that was the issue. Unless you've had the truck for a while then that would be irrelevant. If you're in Phoenix and want some help PM me. I'd be willing to lend a hand and multi-meter.

 

He is in Queen Creek area, little further south. He should be off work soon and can start going through some of the diagnostic steps people provided here