There are a couple of fuses that power up portions of the Instrument cluster. However, as per your description, you may have a cluster that has failed.
I will send a few electrical diagrams that show how the cluster receives its power.
If you plan to check the fuses yourself, be sure to use a 12 volt test lamp to check for power on both sides of the fuse, to both check for the continuity and 12 volt source.
The fuses to check are in the Instrument Panel Fuse Block.
If all fuses are OK and have 12 volts on both sides of the fuses, then you most likely have a cluster that has failed internally. There are companys that do nothing but work on instrument clusters. You can do a google or Yahoo search ( keyword: Dash Cluster or Instrument Cluster Repair.)for these companys. You pull out the cluster and send it to the company for repair.
I hope this information helps.