I assume you checked that the dash light dimmer is not turned to min?

There is a backlight bulb for your clock and it is not uncommon to burn out.
They are readily available at your dealer and they are not expensive. You
probably won't find this style bulb anywhere but your dealer.
The clock easily pulls straight out of the dashboard. You may need to use a
small screwdriver to pry it out, but be careful not to mark up the garnish
surrounding the clock. In fact there may even be a small indent in that
surround indicating the point to pry from. Good luck!
Howard

did you try a light tap with your knuckles?That worked for me.