#1
So I took on my first ever guitar modification project. I have a schecter prototype with two "schecter diamond" humbuckers, one volume control, one tone control and a 3-way switch. I just installed a push/pull volume pot in order to tap the neck pickup. I basically wired the new pot exactly as the old one was wired. The only extra wiring done was to solder the first two poles on the switch to each other and to a ground on the side of the pot. I also soldered the two pickup wires that were tied together to another lug on the switch.

The single coil sound is awesome. The only problem is it hums much more than the single coils on my pacifica, and more than I expected.
1. Is there something I could have done in the wiring to make it hum too much?
2. Will shielding the cavity really help this out?
3. Would wiring all this to the tone pot have been a better choice?
4. If I add the bridge pickup to this switch will there be hum canceling in the middle position?
#2
check that the jack is wired properly. the wires get swapped by accident alot (the inner circular part is the ground lug). also be sure that the coils and pickups are still in phase (try swapping the coil's wires around or using the other coil)
#3
If what Jim says doesn't work, I would just suggest shielding the control cavity. I do it on all of my guitars, and any that I wire for other people.
Acoustics:
1994 Seagull SM6
2007 Takamine G5013SVFT

Electrics:
2008 Epiphone Les Paul Standard Plain Top (Cherryburst)
1964 Gibson Melody Maker D (DC)

Amps:
Traynor YGL-1

Pedals
MXR Distortion III (C4 Modded)