The ignition lock cylinder in your Saturn S-Series operates in a slightly different manner from the ones installed in the typical GM cars and light trucks. Instead of the ignition actuating the ignition switch with the use of a push rod and linkage, the Saturn uses a lock cylinder that is connected directly to the switch assembly on the top of the steering column. Replacement of the lock cylinder requires basic hand tools, and the project is a snap for the average home mechanic.
Disconnect the negative battery cable using an 8 mm wrench and lay the cable aside. Remove the air bag system fuse from the under-dash fuse box. Remove the lower trim panel from under the steering column, using a screwdriver and a 7 mm wrench, and disconnect the yellow air bag connector located at the base of the steering column to deactivate the air bag system.
Remove the steering column trim covers located behind the steering wheel, using a T-15 Torx driver, then remove the five screws from the bottom trim cover. Gently pry the lock cylinder trim ring out of the column trim and separate the two halves of the column trim. Position the steering wheel in the full up position and slip the lower trim cover off the column. Position the steering wheel in the full down position and slip the upper trim panel off the column.
Turn the ignition switch to the "Run" position and then to the "ACC" position. Push the small release button on the end of the lock cylinder housing, using a small screwdriver. Slide the old lock cylinder out of the housing.
Install the new cylinder in the housing and turn the ignition key to the "Run" position to lock the cylinder in place. Turn the key to the "Lock" position and remove the key from the cylinder. Reinstall the column trim and lock cylinder bezel. Tighten the five T-15 Torx retaining screws snugly. Avoid over-tightening them and stripping the plastic trim -- they should only be tight enough to secure the trim panel.
Reconnect the air bag connector. Reconnect the negative battery cable. Watch the "Theft" light on the dash and wait for it to stop flashing. Start the engine. Reinstall the lower trim panel under the driver's side of the dash.
