Mark,
Most of these trucks have trashed wiring so if you're going to be messing around with it anyway, why not just go all the way and rewire it? The aftermarket wiring harnesses from Jim Carter or American Classic are pretty good and come with step by step instructions.
On the headlight switch, there a hole in the underside of the switch body -- stick an awl or small pick tool up in there to release the detent that holds the knob post in. Look around the body of the switch (you have to lay on your back under the dash ...) and you'll see what I mean.
Good luck.
John
