Wiring ? in 90 Daytona

[streetmaster42]

I have a 90 Daytona with a 2.5 4popper that seems to have a bad short in it somewhare, because one of the wires on the back of the alternater glows red hot, while the motors running.

The motor starts up ok, but the wire glows right were it bolts onto the back alternater, but does not smoke though.

A buddy of mine says that its, some kind of back feed from somewhare. So if anyone knows what would cause a back feed, please advise.