So I'm normally pretty good about these kinda things, but I'd like a second (or third, fourth, etc) opinion before I just go for a total teardown on the electronics:
Charvel 475 Deluxe Exotic, in HSS, with 3 knobs - Volume, Tone, and what I assume is the jackson JE1200 boost circuit. I get fine output out of both the single coils, but when I swap to any configuration with the bridge pickup, I lose almost all the output completely. Originally it was wired black to the switch, green and bare to the pot, but jackson pickups are normally green hot, black ground. So i switched those 2 wires, but the sound didn't change one bit. The wiring is a total rat's nest, so the original owner of the guitar obviously fucked with it in some way, but I'm not really sure how because I can't seem to find an original wiring diagram for it.
the 5-way is one of those shitty plastic ones, do they just quit after 20 years or so? That's my first thought, but I don't know if the JE1200 is only connected to the bridge pickup or if it's on all 3. I'm totally fine with the nuclear option, and I'll put different pickups in instead of the stock pups (The bridge pickup seems to have been replaced, as it's got the white paint on the jackson logo, while the 2 singles have long since lost their paint.) on my old Model 4, the boost circuit was integrated into one of the pots, but here it's just loose in the cavity, though it's wrapped in some foam to prevent it from shorting -- This leads me to believe that the pot was replaced at some point. The battery is checked and working, as well, and I've contact cleaner'd all the pots, as well.
Any ideas on where I should look first to see if I can fix it before I just tear everything out and start from scratch?
Could be the switch (the plastic ones definitely die and are easy to "cook"), could be the dude wired it wrong (make sure the coil split wires are actually soldered together correctly), could be the JE1200 is screwed up (although it's usually just in line with the pickups, so it effects all three).
These might help: