The Gen 3 instrument cluster had one bulb per gear indicator. The “D” bulb could be burned out. The gear indicator at the shift lever had one bulb that backlights all gear selections. Moving the shifter causes an orange mark to move to the selected gear.
Changing the bulb in the instrument cluster is easy, but best view the service manual before taking things apart (see link below). The bulb may be available at an auto parts store but I pick them up at the dealer before taking things apart.
http://oregonstate.edu/~tongt/camry
