Just trying to double check my understanding of the awful wiring diagrams.

There should be 12V on the big yellow wire at the relay board in the engine compartment when I turn the key to "start"?

If the answer is yes, is there a(n easy) way to see the connetions inside the steering column?

If the answer is no, what signals in the engine compartment get 12V when you turn the key to "start"?

Last question is a bonus:

Does anyone actually understand the ignition switch diagram in the wiring diagrams? I mean, I can't be the ONLY one that has no clue what the pretty picture is trying to tell me about what electrically happens when the switch is turned.

Yes.. the big yellow wire should have 12v on it when the key is in the start position.

If the car is a 74 or 75, check under the passenger seat for the big brother relay. It probably is the source of the problem.

Otherwise replace the electrical portion of the ignition switch. The plastic wears and finally breaks, causing a no crank condition.