pickup problem with single coil and humburking

sir,
I have a pair of single coil and humburking pickup in my guitar.the neck is single coil with .047mf capacitor and bridge is humburking with .022mf cap. in this waymy guitar is working.
if i selected either neck as single or bridge as single it work fine. if i want to work together in parallel face the single coil is mute. no responce from neck. why? both pickup has indivigually nolume and tone pot. they are 250k. please help me out to work both together. and can u suggest me a good pair of capacitor for neck and bridge pickup?