2006 Suburban Bose nav audio problem

My 2006 Suburban has a Bose stereo system with navigation and lately while using the radio the screen suddenly goes black.The stereo system still functions, but is interrupted by "audio clicks" which remind me of a loose speaker wire.When the screen is black like this you cannot use any function buttons on the stereo but the controls on the steering wheel still control stereo functions.If you turn the system off there is a good chance that it will not turn on next time you try, although it always eventually does turn back on.The cd player works despite this problem but the nav system is erratic.These symptoms occur while sitting still or while moving.I would like to know how to at least get access to the rear of the stereo without destroying the dash, and any clips that might be involved.