Very straightforward setup on this little bass, the photos don’t show how dry the fretboard was. Oil your dark wood finger boards to keep your guitar working and looking its best.
The owner had complained that the switch wasn’t working correctly but I could find nothing wring with it electronically. I tightened to contacts but I suspect the switch is quite cheap and this may be an intermittent issue and replacing the switch with a good quality might be the only solution.