Lighting Nightmare

ok heres my problem. 73 dart sport. headlights, brake lights, and turn signals work. marker lights, tail lights and parking lights do not. i checked the switch. 2 old switches and 1 brand new switch and they all do the same thing. But when i run a jumper wire (from the power comming to the switch to the 2 wires that control the lights that dont work) they turn on. which is telling me that there is not a break in a wire. ive looked over my wiring diagram numerous times and still cant get the lights to work right. anyone have an idea?