OK. I'll take a stab at this.

Most, if not all of the earlier 1st Gens, IIRC, came wired for fog lights. That is, the wiring harness was there, just not the lights or the switch on the steering column. However, you say that you have the switch. That would lead me to believe that the truck had fogs originally. (You could chase down the code in the VIN to find out, but that's really not needed anyway. Just turn the switch on and see if there's power going to the connectors. Remember too that the fogs won't work without the parking lights on at a minimum. Low beams maybe. Don't remember for sure.)

Anyway, if it had them originally, the next question is wattage. The OEM fogs on the '01's were only 35 watts. '02's and later they switched to 55w. So now we talk math. 35w x 2=70w. Divide that by 12 and you'll come up with about 6 amps. If you had 55W fogs, it would be (110/12) or 9A. I point this out because I don't know if they used heavier gauge wire for the bigger bulbs or lighter gauge wiring for the smaller ones. Maybe, maybe not. But you'll need to check BEFORE you add higher wattage bulbs.

That being said, if things check out and you decide to use the stock wiring, all you'll need to do is mount the lights and wire them into the stock wiring. Easy-peasy.

Now where to mount them. If you want them USABLE (that is, something bigger than 35w each), you do want them low. Otherwise they essentially turn into driving lights. So the stock location is good. But, I don't think you're going to fit KC's in the stock location without some "modification".

My '03 has stock fogs, but I've also added driving lights on the front. Those were easy and another possibility for you. If you look at the bottom of the grill, where the fascia meets the bumper, there are 2 3/4" bolts holding the fascia on. Take those out and mount your fogs (or driving lights) upside down through the holes. You may need to enlarge the hole just slightly. This is good for two reasons. They will be mounted low and because they then sit behind the bumper, they are also protected from bumps. The downside is that they are mounted upside down. You won't notice it unless you really look, but being upside down, if they aren't sealed well, water can collect behind the lenses when it rains. Mine do, but it drains out. (And an added small hole would solve the problem altogether.)

If you find that the stock wiring won't handle the wattage you want, you can still use the switch and the relay, assuming again that you have the relay as well with the switch. Just replace the wiring from the relay to the stock connectors behind the bumper. The trigger wiring to the relay carries very little current and should be fine for what you want to do.

Hope this helps!