HELP - Wiring Problem!!!!

[69C10@16]

First let me kind of introduce myself...
I am 16. I live in Missouri (a.k.a. misery). I am halfway experienced with trucks. I bought the best ever first truck a 16 year old could hope for, a 69 C10 with the original 307 rebuilt and under the hood and a turbo hydramatic tranny rebuilt same time. Oh Yeah.

Now my problem.

When I turn the headlights on, the dash lights do not work. I have checked bulbs, they are all in working condition. Also when the headlights come on, My Right turn signal activates BOTH turn signals and my left turn signal does the same but it doesnt flash them as the right does still flash them. My Gas Gauge dont work (ever so I doubt it is a part of the problem). All fuses are great and this is only an issue when the headlights are ON. If I mess with the harness connection at the back of the gauges, the lights will come on and my gas gauge will go to WELL over full but I still have the wierd problem and my turn signal indicators always light in this case. When i let go of the harness connection it goes back to the other way. Where nothing works. The generator light seems to be the ONLY thing working properly in this dash. My temp light stays on no matter what (which I assume is because some idiot before me cut the wire to the sensor).The headlight switch is brand new from classicparts.com as of yeterday. I do not know if this was a problem with the old one or not. I never tested it. I could drop the old one back in but it would take me a while becasue my mechanic is supposed to be calling me any day to replace the lower ball joints and the upper control arm shaft for me so I dont want to rip anything out. In the meantime, are there any ideas as to what could cause this WEIRD problem.

I'm sorry this is so long and complicated which is because Im horrible at explaining things verbally and in writing.

Thanks,
Newton