[VetteVet]

The first thing I would do is pull the S wire and jump the starter solenoid with the key on and let the engine start. If the starter hangs, this will tell you that the problem is in the starter not the electrical circuit and then you can pull the starter. If it doesn't do it then you'll know that it's in the key switch or the wiring to the starter.

Be sure to have the trans in neutral or park and or jack the rear end off the ground. We don't want any accidents. You could unplug the NSS if you didn't want to take the S wire off the solenoid.