You should be hook a tech2 up to it and see, i think. I had a 99 Z71 with a cluster would not show mileage too. You could tap on the cluster, and it would light up. I pulled it out and put it back in for some reason years ago, and now it reads miles constantly...lol
maybe it had a bad connection? idk.
2002 Chevy Silverado 2500 HD. CAI, 4.10's, 35x12.50 r17 Kumho Road Venture M/T's. Nelson Tuned.
2002 Z28 Camaro- Small budget cam build. Full bolt on, Custom grind Comp Cam, LS6 intake, 4000 CircleD stall, Nelson Tuned.
2008 Dodge 2500- H&S MiniMax, CAI, DPF delete, EGR delete, AirDog fuel system.