Radio In Mono - AUX Duplicating Mono?

[crazzymann]

Hey guys, I asked about an old Android head unit a while back and have decided to keep my modded OEM for aesthetic purposes. However, now I'm back to the original problem, that lead me to wanting an upgrade. I have a 2004 Pontiac GTO - pretty much the VY Commodore with 2 doors. I have the ancient, yet popular, "Phreddy's AUX mod." However, ever since purchasing the car, the radio and CD audio have been driver's side only - complete MONO. However, when switching to AUX, both sides play - BUT the RH side is duplicating the LH! This is verified by playing known stereo tracks. What could cause this? I opened up the head unit and the Phreddy's mod "seemed" to be installed correctly. I will mention, the car also has a Sony HCB-30 bluetooth module installed too, with factory-style buttons in the center console (if that matters.) I've attached a pic, to make this post more fun.