[QUESTION] Guild Archtop -- 3 position switch does not 'blend' sound from 2 pickups in center position

The title pretty much says it all. Trying to figure out what needs fixing before I crack my Guild Archtop open. It has 2 pickups, and 4 knobs -- volume and treble -- 2 for each pickup. The switch works between the 2, but the center position, which I suspect is supposed to activate both pickups. only activates 1 of the 2.

Is this a problem with the switch? Or something else unique to Guilds?