This is where I have to admit I've never had the upper part of the column apart.
Yeah, when you rotate the key that "actuator rack" and "sector" act like a steering rack & pinion and make the bracket (actuator rack) the rod hooks to crawl in and out which moves the slide ("pocket" referenced in the earlier pic). On my Blazer the slide part of the lower switch locked up and my key cylinder would only move between run and the accessory on positions, I couldn't roll it back to lock and remove the key.
Yeah, when you rotate the key that "actuator rack" and "sector" act like a steering rack & pinion and make the bracket (actuator rack) the rod hooks to crawl in and out which moves the slide ("pocket" referenced in the earlier pic). On my Blazer the slide part of the lower switch locked up and my key cylinder would only move between run and the accessory on positions, I couldn't roll it back to lock and remove the key.

