What exactly happens ,if the ignition switch goes bad or the lock cylinder goes bad, how does the VATS system react?

I am thinking I am having a problem with my ignition switch or the VATS. I put the key in. turn it to run and I get absolutely nothing, no instrument cluster lights. but if I turn it to start, the cluster lights up and the car fires up and then dies immedietely. not just turn over but revs up once and then dies.

is this how the VATS works if the resistance isnt matching up?

 

The symptom I was having with a bad key was the security light would come on but the car would do absolutely nothing as far as starting.

 

If the car tries to start at all, then it's not VATS. When VATS registers the wrong resistance in the key pellet (or no resistance), it turns on the security light (above SES), and absolutely nothing under the hood does jack squat. The fuel pump and starter are both disabled by VATS, so if it's trying to start and then dying, your problem lies elsewhere.