So just to confirm - is the dash board low light too - ie the speedometer/ tachometer are low lights or just the radio.
Also to confirm, theres a little dial usually to the left of the steering wheel that adjusts the display brightness - you didn't accidentally turn that all the way low?
Otherwise - this will walk through how to replace lights
https://www.youtube.com/watch?v=SNZI_jDrEj0