1993 Buick Lesabre location of ignition switch

Should be on top of the stereeing column about 2/3 of the way down. It mounts to the top of the column with 2 small bolts and there is a rod that operates it (can be seen when switch is removed). Sometimes itis easier to get to it by lowering the column down a little

To replace the igniton switch no, to replace the key tumbler yes. If you unbolt the column and let it come down a little you can get to the switch