Mine is out also. I did see somewhere that a member of some forum managed to fix theirs, but I'll have to search again to find it. It was more involved than the other instrument panel lights. If I find it I'll post it.
The two I've been into with the display inop. have been simple bulb failures. They are located under a metal shield which looks to be cadmium plated (most likely something different though). A pair of tabs protrude through the PC board & are twisted to retain the shield. The display bulbs run hotter than the rest, because the shield blocks cooling air; I'd counsel replacement of all bulbs though as they often fail after the radio is disturbed.