Problem with my bass knob....dont know whats up with it?

ok so i got a hifonics brutus bxi 2008d and i got a bass knob or boost knob and when i connect it to the amp the subs dont work, but when i disconnect it the subs make a loud bang, and the bass knob light is red. im using a simple internet wire, do i need a different wire or what, its driving me nuts