I used a black plug with 8 wires that plugs from the deck to the harness from the car. Then there is a second harness that plugs into the wires going into the amp and the wires leaving the amp- bypassing the amp. I understand the sub is triggered by the main amp. I can't even find the sub. On the rear deck inside the trunk the main amp is on the passenger side with wires coming in and going out- thats pretty straight forward. Then, on the drivers side is a smaller plastic unit, maybe 3"x3"x1" with 1 set of wires going in- none coming out. I looked around for the sub-in the trunk, under the seats (front and rear) behind the matting in the rear fenderwells- maybe I don't have a sub. Does any of this make any sence to you?