95 legacy, had alternator and battery tested, both good out of vehicle. in vehicle no charge going to battery. it starts and runs fine (untill the battery runs out of juice) been through the wiring harness and can't find any opens or bad fuses. voltage drop is 0.3 or less both directions. the wiring diagrams I can find show the wires on the plug going through the ignition switch but mine show voltage all the time. the white or yellow one battery voltage and the black one .3 or something ( forget exactly at the moment) Haven't been able to find any information on if these should be hot with out the key or what voltage the black wire should have. any info or other ideas would be appreciated. (I tried two other used alternators and got the same result 12.** voltage same as battery and drops as it runs)

Have you checked the battery cables. Sometimes the cables corrode not just at the terminals where it bolts at the battery, but further back inside the insulation. Check the condition of the cable to see if anything looks a miss.

sanded and rethreaded the grounds and connections when I did the voltage drops just in case, but it didn't help.

sanded and rethreaded the grounds and connections when I did the voltage drops just in case, but it didn't help.

 

Sounds like the charge coming out of the alternator isn't getting anywhere. Follow the wires and see if any of them are cut, bare, etc.

that's what i said:D, I just can't figure out why. big white has battery voltage, plug white or yellow has battery voltage (hot even without key on) black wire on plug no/.3? volts. everything shows no open that i can tell from resistance but I can't tell if or what could be shorted since there is no drain when it isn't running and I can't find specs on what it should read. I don't think the plug should test hot without the key from the diagrams I can find. or if the ecu isn't sending the signal for it to run why is it getting voltage through the plug wire? no blown fuses, no high readings on voltage drop but i don't really know what the wires on the plug should be doing.