When driving, suddenly the car stalled and, when I tried to start it back again, it did not. I provided some current to it and still did not start. I replaced the battery with a different one and still nothing. Does anyone know why it is not starting?

The middle wire on the battery terminal buss bar is getting hot when running. Additionally the car will suddenly die at low speed and sometines the key won't turn. Are the three related. We just got the car as a repo and the previous owner apparently had issues because the middle wire has been spliced about 8" from the termial box and it has a brand new battery. I am thinking it could be the ignition switch. Where can I find an electrical diagrahm