pedal problem

ok, so im setting up my pedalboard with some new pedals. it is the kind with a power source and 2 effects loops to plug into. I have one of thje loops plugged into an epiphone amp. i split the guitar signal with a Morley ABY. Loop A works perfectly. however, Loop B gives no sound. the confusing thing is though, if i turn on my Fuzz pedal, i get sound from the amp!!! it's not as loud as it should be, but i hear the fuzz sound. ive checked all the connections like, 10 times. they are solid. every pedal is working individually, and the cables are all new. does anyone have any ideas?