I'm trying to install an aftermarket subwoofer, amplifier and headunit to my 1999 Infiniti G20T. It has a BOSE already in it. I ran the all the wires and got an wiring harness all connected. the speakers produce NO sound! the amp and sub work tho. so what do i need to do? i was reading online that i need to bypass the BOSE amp but how? or i need an output line converter?? which one is correct?