First I like my 2007 Silverado new body style truck. Good power, GREAT gas mileage etc etc. but the radio stinks. I've owned many cars and trucks in my lifetime. I understand how to adjust radios for sound output. I read manuals like I'm reading a bible. Each vehicle can have little operating differences. The rear speakers on my Silverado do nothing. When I use the fader function to full rear, the sound is barely detectable. Without touching the volume control the front speakers are working at normal levels. I've used faders in all my radios in this way: I adjust the fader to move the center of sound between full front to full rear. Most times I leave it dead center between front and rear. If there is no sound coming from the rear speakers nearly equivilent to the front speaker output, fader control is simply not working. Several trips to different dealers returns the same idiotic result. They compare what sound is being generated by my truck to another truck with the same specifications. There are no radios made that don't function with the fader having nearly equal output available at the front and rear speakers. Even cheap Walmart radios function in this way. Today the service department told me that the radios are functioning as designed. This is a lie. Chevrolet is hiding a flaw in their radios. It's going to cost them big bucks to replace them all. I don't have a basic radio. I have Onstar with navigation. I've seen too many of these trucks with these crummy radio here on Long Island in NY by demonstration through these "service" departments. To top it off the front speaker output is murky. Too much base when announcers talk on FM. I have to turn down the base to easily understand what people are saying unless I raise the volume to approximately 3/4. Every GM product I've owned and own now except for this truck have had acceptable radios. Something is wrong.