Little black wire on my alternator, where does it go?

[ComealongKate]

Hello thank you for taking the time to read this I'm having issues with my truck no matter whether I put a brand new battery in it or whatever all my batteries keep dying and then they end up no good and I have to go and turn it in there's this little black wire coming off the alternator that looks like it's supposed to go somewhere but I can't figure out where I keep looking up on the internet and I can't figure it out I really need this situation taken care of because I can't drive at night cuz if I you know turn on the headlights or blinker or anything then it sputters out and wants to die can anyone help me with this matter I'm a female and I'm not you know very familiar with you know automotive stuff but I really want to learn so any help would be amazing thank you

[alabama_lowlife]

When it has a fully charged battery and you have the engine running, are the battery and/or brake lights on in the instrument cluster? If they are, it’s an indication that the alternator is not charging. Have you had the alternator tested? Most auto parts stores will test the alternator for free.

The black wire on the back of the alternator is the ground. It should be connect to the case of the alternator and the engine or body

[Cusser]

Originally Posted by alabama_lowlife

Have you had the alternator tested? Most auto parts stores will test the alternator for free.

This.

Another good charging test is to read voltage across the battery terminals while the engine is running with DC voltmeter, should be about 13.5 to 14.5 volts. Wear safety glasses/sunglasses for this test.

[dvdswan]

Welcome to the site.

[Supercub57]

Sounds like the capacitor wire broke off.
Should be a small capacitor about 1/2" in diameter and maybe about an inch long that's secured to back area of alternator. Just replace the capacitor