Did it happen all at once or was this a gradual loss? The best case is that there is a bad connection on the ribbon cables that connect the faceplate to the chassis and the display is losing power or its enable signal. However, if the head unit has not been taken apart for maintenance that type of failure is unlikely, particularly if all the pushbuttons work and light up correctly. Electrolytic capacitor failure is a common problem; but, I don't recall any capacitors on the faceplate circuit board.
Displays tend to be pretty durable if they are not abused; but, failure is possible. The display appears to be proprietary, so replacement in kind does not appear to be an option. If the power supply on the board has a capacitor problem that could affect the display; but, I would expect that there would be other signs of problems if that was the case.