usually when putting in pickup and wiring for the first or second time, theres only 2 type of possibilities
1) Everything is working fine
and
2) totally not working or almost working but still considered not fine at all
and the ways to find out why and remedy it are
1) Bring to guitar tech and pay him to do corrective maintenace
2) On your own, go through wiring over and over and over and over again. Trace out every points from pickup to selector swtch to pots to cap and finally to output jack, use multimeter check for continuity for all the solder joints
and the worst case scenerio ever, desolder everything, take out pickup, pots etc.
For pickup, if really sure that its working fine, then leave it alone. If really particular and wanna check it, temporary solder the pickup wires to a 1/4 inch phone plug(hot wire to tip of plug and ground wire to sleeve of plug). Once done, connect the pickup directly into amp, turn volume to safe and low level, take any metallic object(screw driver, scissor etc) gently tape on the pickup. If the pickup is ok, the sound of the metallic object gently hitting the pickup will be amplified thru the amp.
for the pots, again, use multi meter, measure the value and make sure to check the resistance value will increase/decrease from minimum to maximum and vice versa when turning it.
once done, go thru the wiring diagram again, start soldering away.
and lastly, if it sounds too troublesome, just bring to guitar tech and let them do the thing while requesting them to let you know what was the cause of the problem in the first place.
