Yes, just run the replacement cable to the same spot on the fender relay, the one with all the the other wires connected...
The other side goes to the starter, you would not want your starter to stay engaged all the time when the truck starts...
Make sure and insulate the ends VERY well, the 4 AWG crimp takes up more space than the original one, so it might try and become intimate with the alternator housing. I heat shrinked mine then wrapped the hell out of it with electrical tape.