2004 Saturn Ion sometimes won't start

The bcm aka body control module runs the passlock input from ur ignition switch ur ignition switch is the most likely cause pretty common they have like 3 or 4 changes to them since they were new. Best way to diagnose the problem is check the bcm for codes if it was the problem most likely codes would be b2960 and b3033 there pretty easy to change u just have to relearn the passlock for the new switch. Let me know what u find.
Louie