I'm working one a '84 f150 w/ 300 6. The starter only partially engages and is getting chewed up, it's a new starter. Flywheel teeth are good. The starter relay is missing the wire that goes on either the S or I, Where do these wires go to so I can run a new one and could it be the problem.

 

If you are talking about the relay on the fenderwall passengers side, the origionals only had three terminals 2 for the battery leads and one for the coil, all aftermarket solenoids have 4 terminals two for the coil if its the right replacement part you only put the wire on one of them