hey, I just got a wired pickguard from Guitar Fetish for my old Strat. I bought it to drill a killswitch into it, which I did. When i put it all back together and plugged it in, I realized it has the most buzz out of any guitar I've ever heard. The bridge pickup is always really loud, and the neck gets loud as well when I roll the treble knob up to ten. Also, when the volume knob is at zero, there is no hum. As I roll it up to ten, at about 5-7, it gets really loud, then the hum quiets dwon a little bit at 10. Does anybody know whats going on?
Does the new pickguard have metal foil glued underneath it (most pickguards have it)? Maybe that buzzing noise is interference.
It would act as a shield, reducing the hum.

I could be totally wrong about this though.
This sounds like a grounding problem.

Check that all of the components, including the bridge, are grounded correctly, and follow a clean chain to the jack. Make sure that you have no grounding loops.

If you don't know where to start, hit us up with a picture, and we can give you pointers.