The dimmer switches are picky when they haven't been used much to turn on the dome light, once you get to full bright there's a rough detent to get past that feels like you're going to break the switch to get past... I don't like doing it on my Ranger or '98 Explorer, the '00 Explorer seems to be easier if memory serves (I usually use the map lights on those...) my rocker switch stopped turning on the light and the cargo light doesn't work, haven't looked into it...
My '97 Ranger just has the switch in the door latch, no button in the door jamb... to get to the switch in the latch it's probably easiest to get the latch out, it's just the 3 screws right there, the door lock deal and the two linkages in the door, it's been a few years but I don't remember it being too bad... the switch is just held in with a single screw, spray it with WD 40 or electric parts cleaner... I think I have my spare door latch for one of the explorers, Thursday I could take a pic...