The neutral safety switch is only in the start circuit, if your gauges and alarm are not responding they are not getting power from the run “ignition position”. First see if you have 12V on the ignition switch “B” terminal. No power here check the 10 pin connector to see if it’s seated. If you have power on this terminal see if you get 12V on the “I” terminal when the key is in the run position.
1997 2400 SCR
5.7 Vortec / Bravo 2