It does sound like a cluster problem.
You will need to scan the DIC-IPC or the BCM to figure out what is going on a one of the 3 will have some codes stored for the condition.
It is a CAN system , so all the modules are on a party line.
Also as said before it could be a Printed circuit problem. I am leaning toward a Integrated circuit failure on the Instrument panel itself.
A tech 2 or a snap on Modis or a Launch 431 will be able to do output tests, so the gauges can be cycle to determine more about where the problem is.