I think Bill has you on the right track, but in regards to the ignition switch.......
From what I know of them, the car won't shut down completely. When the switch is bad, it effect "accessories", like auto lights and the blower motor. The car will still run and operate, and typically the switch will eventually engage and all your "accessories" will work. The switch can be had on e-bay, look for AC Delco. I think I paid about $75 for mine early last year.