My brother's girlfriend installed her amp, sub, and head unit herself b4 we knew her and ever since then she must remove the fuse for her amp when she turns the car off or the battery will drain and end up dead. Is this an issue with how the amp is wired to the battery or an issue with the turn on wire coming from the head unit. Full disclosure, I don't know very much about electric wiring or car audio. Thanks for your help.