I have a 2004 crown vic, with the 4.6 police motor. When I try to start the car, it turns over, but not fire. We can jump start it and the battery light on the dash comes on, but once I turn it off, it wont start back up. Before the jump, none of the dash lights (check engine, seat belt, battery) wont come on. All relays and fuses are good. Ive replaced the alternator, and ignition control switch on the steering column. Is there something else that will cause this problem? Any ideas will be really appreciated.