Audio Systems: 2004 Ford Taurus, ford taurus, 2004 ford taurus

Question
I have a problem with the audio from my factory installed car stereo. The drivers side front and back or maybe it's just the back speaker keeps going off and on or fading in and out with very low volume. It happens quite a bit. I was wondering if this could be the stereo or the wiring?

Answer
IF you never touch or cut any of the wires or radio, the problem will be in the  amplifier  
it needs to be repair or replace
it looks like this unit and it is in the trunk


http://www.oemautosound.com/pc-229-173-lincoln-sable-taurus-rcu-tunner-amplifier...