07 crown vic odometer not lighting up

Most likely u will need a cluster

My 2008 CVPI does a similar thing. odometer is sometimes very dim or not illuminated at all. Then it works fine for a while.

Check the fuse thats located under the drivers side near your feet

I had almost the same issue you are having. But my entire cluster wasnt working at all. I checked all of my fuses that are under the hood, glove box, and in the car on the driverside by the pedals. My issue was just a fuse.

That is usual issue with those clusters. send to AUTOMOTIVE CIRCUIT SOLUTIONS. They will quickly repair the cluster and you have optional back light color choices.