So I have a 1989 ford f-250 that won't start. I've replaced the starter, the solenoid, and tested the wires for input. All good except I don't know where the issue could be. If you need more information let me know I also am unsure of how it's wired but I belive it's wired correctly and like I said I was driving it that day and came back after an hour and it wasn't starting, side note we tried to turn the flywheel I think with a breaker bar and it was really hard to turn and couldn't start it it's been about 3 months now and think I have to send it to a shop

 

So,,, your saying it wont 'crank' over. Correct?
Turning the engine over on the balancer bolt should have reasonable resistance.
Also,, post the info for eng/trans...