1994 Chevy Suburban Starter/ Electrical

I had a problem with the starter where it grinned but that has been fixed. I bought a new starter and exchanged it myself. But I noticed that on the new starter it had and extra terminal. The old starter only had a Positive along with a smaller wire attached. The newer rebuilt one had an extra terminal and each one had a label on it. One had an S and the other had a P, I didn't know why there was an extra terminal and I've been scouring the web looking for info and can't seem to find anything about it. Now heres the problem, I put the new one in even though it had an extra terminal but I just hooked it up the same way it was before leaving the other terminal undone. After re-installing I started it about 10x's and it worked great & my father even used it. Well later that night he was driving it and had started it about 5x's that night because he was with my mother shopping around, and all of a sudden when he tried to start it, all the dash lights got dim and smoke came from the hood. My father noticed that a small gauge wire was burned from the battery junction block, and he says this wire is called a Fusible link. I have no idea why that would burn up but I guess my main question is, by leaving the terminal on the starter open, could this have caused this electrical problem, he even fixed the fusible link with some wire and it still did the same thing with the dimming of the lights. I thank you fr you hasty replies.