I had the same thing happen on mine. It has a bulb that you can change from the back on the instrument cluster. Hoping that it's just the backlight and not the whole LCD display. If you can still read the temp numbers then it's pretty easy.
Search around for instructions on Instrument Cluster removal. There are some step-by-steps. The bulb you have to purchase from the dealer or Fastlane and they will know which one it will be. (smallest blue plastic based ones I think)
I took notes when I did it, so if I have more time I can post photos.
-Apine CD changer