I have a 1990 nissan maxima. I put in a new alterantor today and there are two wires from the car,I know that one goes to the battery thing on the alternator. The problem is what is the other one? Does anyone know. Help would be nice.

 

craig's got a nice pic I think.
The other one attaches to a screw on the backside of the alternator and acts kinda like a ground.

 

You should have 3 connections:

1) connector that plugs into the alt
2) terminal that attaches to the regulator output (stud)
3) ground that attaches to the alt with a screw

tim