97 buick ultra supercharged. what module will keep my car from starting. I sometimes get an air bag light; other times a trak light. voltage light used to always come on but everything tested ok. the diagnostics don't throw any codes. I replaced my alternator and the plug to plug it in... no help. where do I go from here. It turns over but won't start. Has gas. I recently checked my brakes and a oil change where they replaced my license plate light. Thank you!