Just picked up a project guitar that was void of all electronics for 30$ and I have come to the conclusion that this isn't working so well. There are 2 pickups, 2 volume pots, one tone and a 3 way switch.
Basically I have the 2 pickups going to their individual volume pots <the top right pot has the ground wire from the bridge soldered and the top left pot has a wire going to the back of the tone in an attempt to ground>
From the volume pots the signal goes to the 3 way switch and the switch goes to the tone and then to a TRS output jack with the ring and sleeve soldered together.
I've looked at schematics but they only further confused me. I can imagine there is a simple answer to this. I've tried multiple combinations of wires to wires and nothing seems to work.
Specifics about the hum:
-half of it goes away when I touch the strings.
-When I turn all the knobs to 0 the hum remains (and is still slightly affected by touching the strings)
-it's really annoying
touching any of the metal on the switch specifically gets a tremendously unpleasant sound too.