This is on a 2007 Tahoe LTZ. It has front and rear AM/FM/XM and also has a factory DVD system. All components are straight from the factory and un-modified. The system has functioned great until just recently. It started with the turn signals making a loud whining noise over the rear speakers. Now it has progressed to add a definite engine noise over the rear speakers. Mostly it seem like it is the rear passenger side speaker. The strange thing is that you can turn the rear radio on/off a couple of times and the noise goes away. Has anyone else had this problem and what did you do to fix it? This is my wife's ride and if momma ain't happy, nobody's happy. Thanks in advance for any and all answers.