On my alternater I have a plug with a black and a red wire, where does the black one go?

 

There should be a stud with a nut on the back of the alt.

 

I know the stud goes to the battery but where does the black wire go coming out of the plug? it appears to go trough the fire wall

 

It goes to an idiot-light or volt guage, I think I've heard it has something to do with charging, but I'm not sure what.

 

Well my volt meter works but The alternater still wont charge. I hooked a wire from the black wire coming out of the alternater plug to the battery and now it charges. I cant figure out why it wont charge with out this wire?

 

3 wire alternators are wired as follows.

the stud on the back of the alternator has a large wire from the positve side of the battery attached to it. This connection usually comes from the positive terminal on the starter. (the original wiring has a fusable link in this circuit. If you run the large wire from the battery directly or from the terminal block on the side of the Rad cradle make sure it has a fusable link in it.)

The Wire attached to the #2 terminal goes to the stud on the back of the alternator this is the exciter wire, tells the alternator when to charge.

The wire attached to the #1 terminal goes to the gage or light on the dash which ever you have.

Ric

 

It should be dark brown and goes to the c/h fan 20A fuse.
The fuse is hot only in run and sends switched power to the regulator.