I replaced the solenoid and starter on my 1990 Ford F-150 but it still won't start

Look for a little hole under the ignition and a tiny screw driver that will fit in it. turn the ignition switch to on and then push on the screw driver and the ignition should slide out. Pull the key tumbler out and then use a large blade regular screwdriver and try and start the truck with it out. If it starts you found the problem, if not turn that slot back to the "run" position and put the key lock tumbler back in.

Same issue- BUT, if I run 12v directly to the S screw (the control circuit) it starts. That tells me the solenoid/relay is working, but that the ignition is not providing sufficient voltage. The key does click a relay under the dash, so I don't think it's the steering column... still perplexed and starting my truck with a screwdriver.