Welcome,
Be sure to look in the "Engine" section of the forum for links to free downloads of the service manuals. It is probably covered in there. I just posted this (admittedly crummy scan) pic of the tilt column breakdown from the manual; might give you some insight. Of course if your truck doesn't have tilt it's slightly less complex.
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Haven't heard of your particular issue before, so it just may be that it doesn't happen enough that someone has made a video on doing the job. Usually ignition switch issues on the old style column (pre-1995) tend to be the tumbler goes bad and won't move to a particular position, or the electrical part of the switch (which you've already discovered is not insid the column, but farther down on the tube) goes bad. A third somewhat common failure mode is on the tilt columns, if the tilt assembly gets loose enough, it could interfere with the operation of the actuator rod between the tumbler mechanism and the switch.
Richard