Good morning2004 coupe and the stereo is the infinity stock unit. I want to keep it stock. Stereo works as far as display goes but I only get sub woofer for sound. I have replaced the amp with a working unit from eBay but the issue still persists. Anyone have any ideas where to start looking? I am not a stereo guy but am pretty handy. Outputs from the stereo head unit have been checked and they are all good .