Where does the "alt excitor" wire go?

I'm wiring the alternator. Looking at the wiring diagram in the fsm, it makes perfect sense. The field, the ground and the aux leave the alt to go to the harness. A wire goes to the gauges and then the main goes to the solenoid. So where does the alt excitor wire go that came with my ezwire kit? It comes from the fuse box I believe, and I would think it goes to the field, but the only field wire in the wiring diagram goes to the voltage regulator. The phone line for ez wire is closed now. I am gonna wire it skipping the alt excitor wire and see if its good. Anyone know the destination of this wire?

 

Should be wired to a key-on circuit.

 

Doesn't it go to the idiot light ( warning light ) then to the alternator?