Newbie here. My Mexican P Bass didn't have any issues with humming to start with. I replaced my stock pickups with SD SPB-2's and Both pots, switch and jack with a CTS, Orange Drop and Switchcraft kit. I noticed that there was a humming when I tried playing it. Whenever I touched the bridge the hum went away. I have it wired exactly like the Setmour Duncan diagram. Originally there was a terminal screwed to the wood touching some graphite looking paint which is wired to the volume pot housing. I never put that wire in since Seymour Duncan's diagram didn't show it. Is this why it's humming? I don't have any other shielding in the cavities. no foil on bottom of pick guard or inside pockets of pickups or control cavity. Please advise guys.