Audiopipe apnk 250.4 low pass problem

So I bout a new audiopipe apnk 250.4 and I'm running 2 10 audiobahns on it I have it hooked up with a voice coil per channel,therefore using all 4 channels. I am having a problem with channel 3-4 low pass, no matter how I hook it up I'm not getting much sound at all out of those channels only on low pass. If you put the crossover on high pass or full it works fine thanks in advance for any help.
 
Are you sure that you don't have the speaker wires reversed on ONE voice coil of the weak woofer?

Set both gains and both low pass pots to fully clockwise. Set the bass boost to fully counter-clockwise.

Remove the bass control.

How do the channels compare with those settings?

How does the level of the channels compare with the speaker on the individual channels (no bridging)?