Dauntless Starter Issues

So, I have a new/rebuilt starter from Delco, and a new wiring harness. So everything is new.
Problem is when I turn the key to start the starter turns the motor and continues to turn the motor over until the battery is disconnected.
I replaced the key switch
Double checked the wiring and I'm not seeing any issues.
- Wire from S terminal on switch to S terminal on solenoid
- Wire from R terminal on solenoid to Coil (disconnecting that wire made no difference)
- three wires from B terminal on solenoid, one to battery one to alternator and one to fuse box.
Is there anything else I can/should check before assuming I have a bad starter/solenoid?

 

You can check by dropping the S(purple?) wire and jumping the S terminal to the main lug. If the engine keeps cranking after you remove the jump lead, you have a bad solenoid.
If it stops cranking, then you have an issue with the ignition switch or;

some sort of feedback in the ignition switch to solenoid wiring.

 

It sounds like a bad switch or it is wired wrong. Disconnect the 'S' from the solenoid and crank engine. Check 'S' for voltage.

 

I disconnected the S wire, jumped the terminals got the same result.
Just keeps on cranking until the battery terminal is pulled..

 

Looks like you isolated it to a bad starter.

 

Thanks, I figured it was.
That wiring harness was new but I got it in trade some years back.
Was sketchy as hell, had missing circuits, dead end circuits and the like and honestly there's not much to a Jeep.
The company that made it is out of business so it had me second guessing myself.