Help, Alternator wiring problem, Ground wire??

[RamblerRogue]

Hello, I am new here and working on my brothers truck for him-1998 Nissan Frontier 4cyl 2wd. He was/is having a problem with the charging system. He installed a new alternator with no results then a new battery with no results (When vehicle is running it is simply draining the battery). On the alternator there is the positive wire and the plug and coming out of the harness in the same location is a large black (12ga) wire that is not connected to anything. Is this a chassis ground? We need to get this truck back on the road by tomorrow night so any and all help is greatly appreciated. Thanking You in Advance, Chuck

[Ken@PTUNING]

You should have the main battery wire that attaches to the large lug post on the alternator, the harness plug (two wire), and lastly a black wire with a ring terminal. That gets attached to the alternator housing (any of the remaining screws). Hook that last wire up to the alternator housing.

[RamblerRogue]

So that is simply a ground for the alternator so it will complete the circuit and charge? If that is all that I have to do that is awesome, Thank You!!!