Won't start. Batt ok

If when putting power directly to the relay gets the vehicle to start, then the likely failure is the ignition switch or the fusible link coming to the ignition switch.

What I would do is go to the switch and check for 12 volts coming into the switch and then out when cranking the engine.

If you have in but not out, then the switch is the issue.

Here is a guide that will help with this:

https://www.2carpros.com/articles/how-to-check-wiring

Also, I am attaching the wiring diagram below but I know you tested the wires but we need to double check this because there is not much on this truck, so it is either the wiring or the switch.

Let me know what you find and what questions you have.

Thanks