Ok. I've got a 1995 4runner 3.0 auto 4x4. My alternator isn't chargeing my battery. My battery sits at 12.3v connected to the cables not running. So the batteries good and I have no electrical drains. With the vehicle running I'm reading 12v at the battery and alternator. My original alternator passed the auto parts stores test and came out good. But I went a head and bought a new one for the hell of it. So I put the new one in. Same thing. 12v at the battery and alternator. I've cleaned and checked all wires and fuses. They're all good. I don't know if it has anything to do with this, but my battery light doesn't come on while plugged into the dash even with the key in the "on" position. I've taken the dash bezel out and checked the bulb with my power probe. It came out good. I tried it with the bulb in the bezel and it came on. I'm a little lost. Help!!!

 

First things first...
1) Do not just replace parts and throw money at a problem without first verifying that you are replacing a broken part.
2) Open circuit voltage (no-load) of battery is not enough indication that battery is good. Need have it load-tested at auto part store. Quicl check before you drive off to store, measure battery voltage with engine NOT running, with AC ON, High Beams on. If battery voltage stays abive 11V, then, it's probably OK, but still take it to store for testing

Explanation of how charging system works (see my sig) shows check points where you need to measure voltages to see if parts that are connected to alternator are working or not.

 

Could be something as simple as a poor ground .

Could also be the wire from the B terminal of the battery has broken down from old age.

Just how old is your battery??

 

Correct. Measure voltage at B post of battery. COmpare to what you read at battery. If significantly different, then broken "B" wire.

Batteries go bad in 3-5 years.