Saturn L200 service and security lights

I have a 2001 Saturn L200. Recently, the service and security lights would come on intermitently when the engine is started. When this occurs the fuel and temperature gauges drop to zero and the AC will not work. Today, it failed to start completely. I replaced the ignition switch and was able to get the car to start after several trys at the 30 minute passlock reset. The car starts but I still have the service and security lights come on occassionally and when this occurs the AC again does not work. Any help would be greatly appreciated.