yep it will sound like a pickup at full volume/tone if you wire it direct, bypassing all the goop in the middle.

not sure if your switch has 8 lugs (never made a PBG tele) but this is a nice diagram to help diagnose.



If you have a multimeter you can also follow the signal from the pickups through the circuit to see where it gets killed. Put one probe on the pickup's hot wire and one to ground and follow from pickup selector, to volume lugs, to tone lugs, to output (that is - changing the 'hot' probe's contact to each of those)