[VetteVet]

Actually if you noticed on the diagram it says in certain circumstances a diode may be needed. Those circumstances are when you don't have a warning light and have an amp guage type dash, or you just don't have the warning light. If you have the warning light then all you should need to do is to run the brown wire from the light to the no. 1 terminal. In the stock harness the brown wire goes to the old external regulator on the radiator mount next to the horn. The other end of the regulator is either a white or a blue wire and that runs to the alternator no. 1 terminal. Most guys just run the brown wire direct to the new alternator if it's long enough. This is all explained in the FAQ post by Toddtheodd that I referred to in post #3., and again in the link in post 5.
Try this wiring and see if it works and if not we will get back into it.VV