1997 Cadillac STS Ignition Switch

First of all, why do you feel you need an ignition switch? Are you experiencing theft system problems? If so, you are after an ignition cylinder, not a switch. To replace the switch, you would lower the steering column to access the topside of the exterior where the switch mounts. An ignition cylinder feeds through the column, and requires steering wheel, sir coil, lock plate, and turn signal switch removal, for starters.

Try to remove the old ignition lock cylinders, in which you have to remove the steering wheel and the battery cable and the brackets. place the ignition cylinder on the steering column tube and place the new bolts in place and tighten them as to hold the switch in its position. Hope it helps.