My navigation screen is black and the radio buttons won't work. I can still use my radio through the steering controls but not the CD player and the radio has noise spikes randomly, if it is up high the noise drops down, if the radio is turned down, it spikes way up. The navigation screen gets a little brighter when the radio spikes up... I loved my Yukon until recently when the speedometer gauge had to be replaced last year and the sunroof has fallen apart...Time to trade it in, but I owe twice as much as it books!