The 1st place that I would check would be the fuse box (NS). In case you dont get the problem solved soon may I suggest you do what I did a few years ago in a Buick I had? When my DL's went out I just taped a small cheap flashlight to the steering column to illuminate the dash, It wasn't as good as the dash lights but at least I could see the speedo at night. Good luck to you!
Is it just the instrument cluster illumination that doesnt work or do ALL dash lights not work, like light switch / dimmer control illumination, radio night dim, clock dim, etc. If OZNLY the actual instrument cluster lights dont work, but others do, it is NOT a blown fuse.