Bought a used radio from another member to replace the crappy aftermarket one that came with my 02 P5. Seller claims it was working when shipped but when I installed it today the volume knob does not work. When you turn the knob no volume increases both in sound and on the screen. pushing it in will turn the radio on and off but when you turn it nothing happens. Has this happened to anyone and has anyone found a way to fix it. Please any input would be awesome. Thanks
