1994 Pontiac Grand Am ignition switch

1994 Pontiac Grand Am mileage: 120,000. For the past few months I have had occasional starting cutting-off problems. When I turn the ignition switch to start, sometimes the panel lights will not come on. I continue to turn the switch off and on (anywhere from a couple of turns to a couple of hours) until the panel/dash lights do come on. Once the lights come on, it starts and runs like a charm. At times, even while I am driving, for no apparent reason, I will hear the automatic door locks unlock and the engine will suddenly just die. Once or twice while traveling at highway speeds the doors would re-lock and the engine re-start as it coasted, before I could react it would be just fine. I find this very annoying, not to mention dangerous. As always, when ever I have taken the car into the dealer, it works perfectly fine. I hope that I have provided enough information so that you may narrow down what the source of the problem. Thanks.