Sr20probs

Hey guys I know google is still around but my problem is kinda weird I guess or I’m just not the brightest. Anyways, when I turn the key it clicks once but doesn’t even try to engage or turn the starter. Any ideas why it’s doing this? Would a entirely new engine harness from wiring specialties fix this issue? I just want to drive it. I replaced the trans harness with a wiring specialties one. I have 12v to the starter. I’m able to jump the solenoid and it spins. No engagement. Thanks I’m prepared for some “your a dumbass” comments but it’s okay I probably deserve it lol.