[gmc684x4]

This is for the non computer controlled Cs130/144 alternators
the non computer controlled alt has 4 pins

worst case you can change the headlamp harness to 69 72 upgrade harness and use EC82 Adapter with resistor (napa)

I do not know what wire diagram to look at for a ecm controlled alt

brown wire in your circled picture is for brakes

Diagram note brake light loss pressure wire I placed in the wrong spot look at diagram lower down