Thanks for the info! Your theory makes a lot of sense based on the photo you shared. The bridge pickup looked a little janky to begin with, but I attributed that to a less than ideal pickup replacement job. Good sleuthing!
It sounds pretty good and manages to stay in tune. The jack and pickup toggle are in rough shape, as both need a wiggle sometime for the guitar to output a signal. I wanted to figure out what this Frankenguitar is, so I could better decide what kind of investment to make in it. It's probably overdue for a tune-up, as I've owned it for 10 years but it doesn't get as much love since it's no longer my primary electric.