Headlights cutting off

I have been having an issue with my headlights for years now. They cut off randomly and more frequently in cold weather. I would make them come back on by flicking my high beams on and off. Through a very long process of elimination I have found that if I wiggle the wiring harness that is under the fuse panel in the truck my lights will come back on. It is really hard to determine which wire leads to the headlights. I feel like it's just a loose wire in the male plug of the wiring harness.

Does anyone have a wiring diagram?
I could use all the help I can get!

Thanks,

Justin