Hum gets louder when I touch the pickup selector. Is this a grounding issue?

[PorkRinds]

I noticed hum increases when I touch the metal washer on my pickup selector. This doesn't happen when I happen when I touch other metal parts on my guitar. Hum gets quieter when I touch the strings, tuners, bridge, etc.

Anyone know what's going on?

I should also mention that I bought this guitar used and it seems like whoever did the wiring accidentally wired the bridge tone as a second volume.

 

[Noodling Guitars]

it could be a multitude of things, including possibly some loose wiring on the pickup selector that causes a grounding issue. I've seen Epis where even from the factory they had to add some tape to make sure lugs from the switch don't accidentally short out when it touches the side of the cavity (on models that have shielding paint). It could be something similar to that where your switch is properly grounded when you don't touch it, and when you touch it it's just enough to move the grounding wire loose - but seriously it's just a hunch.

If you are able to solder, I would just just take it apart and do a once over on the wiring. Should take at most 30 mins assuming you're familiar with the wiring schematic.