There are two primary components for normal key start function with any saginaw column. The key tumbler and the ignition switch. Either of which could contribute to the failure you're experiencing. The easiest one to deal with is the ignition switch mounted on the topside of the column about midway down and behind the instrument panel. To access it, you will need to remove the plastic column shroud and the instrument panel cover. It could very well be that this switch has bound up preventing your key tumbler from rotating properly, as the two items are connected via a metal plunger rod. If you find that the key tumbler will rotate freely once the plunger rod has been disabled, you know the switch itself is the problem. This can be further confirmed by actuating the plunger rod by hand. If the movement seems forced or sticky, the switch will need to be replaced. There are two switches available. One for a tilt column and one for non-tilt. You need to get the correct one to match your column style. These are common replacement parts which can be purchased at most any parts store. You could swap columns between scouts as mentioned, but then the issue you're left with is mismatched door and ignition keys, so try the diagnostic approach as suggested above first and see where that gets you.
