For 1990-2009 cars

The park/lock system prevents ignition lock cylinder movement to the LOCK position when the automatic transmission shift lever is in any position other than Park. A lifting magnet (solenoid switch) in the steering column impedes the ignition lock cylinder travel. An open switch in the A/T shift lever controls the magnet when the vehicle is in Park. When the vehicle is shifted out of Park , the switch closes, and the lifting magnet is energized. This prevents ignition lock cylinder travel to the LOCK position. When the ignition key is inserted, the lifting magnet receives a constant power supply.