I have taken the bose amp out from under the passenger seat. I have rca's from the HU to the 4 channel amp for the 4 speakers and rca's from the HU to the sub amp for the sub. The sub doesn't do anything. It likes its not getting a signal. I know the sub/amp works because prior to the new HU i tapped into the front speaker signal from under the passenger seat. Anyone have an idea what is causing this?