1988 no crank, and starter spins when jumped but won't engage with flywheel

[Ryoung40911]

So I just got done reassembling my 1988 after a bunch of work including removing the criuse control and it's wiring. I went to start it, and got nothing. The lights on the dash turned off like they should to send the power to the starter when the key was turned, but the starter won't turn on with the key. If I bridge the 2 large terminals on the starter, the motor spins, but the solenoid won't engage with the flywheel. My starter has 2 large red wires (one smaller one bigger) and a yellow/blue wire that appears to go into the firewall and somewhere to the ignition switch. I have absolutely no clue what could have caused this, because I didn't mess with the starter while working on it, and the car started a month ago before I parked it. Any ideas on how to troubleshoot this would be appreciated, as I'd like to verify if the starter is actually bad before I go spending money to replace it. I'm pretty terrible with electrical, so I'm currently at a loss.

 

[DET17]

Got access to the Green book which details starter functions? I've skimmed mine and the 411 is excellent. If you can find a copy online, read it thru (theory of operation for example). Since the starter spins, you are close but something still amiss.

Battery fully charged? You should still see at least 11Volts, maybe 11.5 at the + terminal DURING cranking. Have someone confirm that voltage asa starting point. If you didn't touch the starter or control wiring during the downtime, the batter would be my first suspect.

 

[hiperfauto]

To activate the starter connect the large red wire to the yellow/blue wire. By connecting the 2 large terminals you are powering the motor but not the solenoid which is what engages the bendix with the ring gear on the flywheel/flex plate.