My 16 year old son just bought his first vehicle, a 1986 Ram 150. The truck is very original and rust free. I'm having a problem with the exterior lights. The parking lights, taillights and instrument panel lights don't work. The headlights work, the turn signals work and the brake lights work so I know the bulbs are good. The fuse for exterior lights in the fuse panel is good. I replaced the headlight switch figuring that all of these lights intersect there but it did not solve the problem. I'm stumped. Any ideas?