Black Screen

[BobS]

Lately after a few minutes after strating the car the the screen will go black. The units continues to work as the radio just continues to play. Also the touchscreen still works but the light on the buttons go off too. After switchting off the car and restarting the screen stays black. But the next morning the screen is on again for a few minutes before going balck again

Any suggestions to the cause

regards

Bob