[Dr Sparks]

No doubt after these many years the lock cylinder and switch body are tired. At any rate, it could also be a case of misalignment of the switch down on the lower end of the column. The switch mount bracket allows the switch to slide a bit for proper alignment with the actuator rod, which is operated by the turning of the lock cylinder. To slide the switch body into alignment you loosen the two 5/16" hex head fasteners on each side of the assembly, which is located on top of the column, lower end. Slide assembly up towards the wheel, against the rod while your other hand turns the lock cylinder until everything feels and operates normal again.