wiring harness installation ???

I have a '94 AWD and want to install a 5 prong wiring harness. Can I get some insight on the location and/or procedure for installing this ? I have a small utility trailer that I want to start use.

Not sure on '94, but my '97, the wires are installed at the factory. I found mine inside the passenger side jack cover. They were stuffed rather high up the pillar, covered in black tape. Mine were the correct color code for a 4 wire connector, plus a few extra wires.