Headlight Problem - Please Help

[itaintez]

I lost headlights a couple months ago and still can not figure it out. When I turn on my headlights all the proper lights come on and work except the headlights. If I mash the floor switch, the brights and the headlights come on together like they should. So after reading forums I replaced the headlight and the bright lamps. No luck there. Next I replaced the floor switch, no luck there. Today I replaced the headlight switch behind the dash and still no luck. The switch sticks so I will be sending it back for another, but I don't think there is anything wrong with it.
The only thing left I can think of is wiring. I am not an electrical person, but I have shallow pockets so I am trying to figure it out. I can't find a diagram on what wire does what to the headlight/dimmer switch, but if I knew what did what I would have an idea of which wire to trace. Does anyone know where I can find a diagram on this? Has anyone else had this problem this bad? What could it be and please don't just say grounding issues - I can't find any, but I am no expert. This is my 72' Jimmy and it is driving me nuts. It also doesn't start, but one issue at a time. Thanks for any help in advance. -Nick