09 Malibu, replaced all speakers, added a four channel amp, high power. Kept factory head unit. I didn't want to mess up Onstar. Apparently, Onstar as well as all warning chimes and turn signal noise are audible through drivers door speaker. However, now that I've amp'ed the system, all those things are also amp'ed even when stereo is low or off and way to loud. Is there anything I can do to remedy this situation? Thanks for helping.