Weird grounding issue, ungrounded coils?

[shoryuXE10]

My guitar buzzes. Like, a lot.  :help:

It was my first wiring job. 2 humbucker, 1 vol, 1 tone, 3 way blade, nothing fancy.
I followed this diagram from SD: https://docs.google.com/gview?embedded=true&url=https%3A%2F%2Fwww.seymourduncan.com%2Fwp-content%2Fuploads%2F2016%2F05%2F2H_3B_1V_1T.pdf

I know part of the buzz comes from me not shielding the cavity, but..

Touching nothing on the guitar -> Loud buzz, horrible hissing noise when vol and tone are both past certain points (about 9 and 4, respectively)
Touching strings, bridge, pickup poles on the south coils, pup screws, tremolo claw/springs, pots, output jack -> MUCH quieter buzz (no surprise, should all be hooked to ground)
Touching the 3-way switch, switch screws or pup poles on the north coils -> Slightly louder buzz and a horrible hissing noise no matter the vol or tone settings???

I've already tried reversing the two wires on the output jack, so I know that's not the issue. None of the wiring diagrams I looked at had a ground wire for the switch. What could be wrong?

Sorry if this sort of question has been answered before.

 

[Cagey]

Shielding the cavities won't do much for you. But, the cables coming from your pickups have 4 insulated lines and a bare wire. The bare wire needs to be grounded or the shielding wrap in the cable isn't doing anything for you. Also, if the line from the switch to the volume pot is much longer than an inch, it should be a shielded cable, as well as the hot line going from volume pot to the output jack (be sure to ground the shield). Take care of those issues, and the guitar should be somewhere between quiet and silent.

 

[Logrinn]

Could you post some pictures of your wiring?
Are the pickups Seymour Duncans? If you're using another brand you have to be aware of different color codes of the wires.