Glad you are enjoying that bass!
I was gonna ask "what switch?" But I think see a small silver switch right next to the tailpiece? Not sure that was a factory install, possibly a later mod. But typically a switch in that area would either be be to turn on and off the neck LEDs (if installed) -or- to switch the 1/4" jack between mono and stereo. If you can post any in-cavity pics we could probably tell you. Or you know, just try it and see what happens.
Sometimes as an incorrect reaction to RF noise people will add ground wires, maybe try to "ground" the bridge or tailpiece. But that method is a holdover from passive basses and doesn't apply to our instruments. It won't hurt, but it won't do any good.
Jimmy J