Gauges going wacko 2003 chevy silverado 1500hd

Hello there and welcome to fixya
This is a issue that both GMC and Chevrolet has had in the past the problems stems from a faulty controle module that makes the dash go crazy or just simply not work at all
The dealership is responsible for replacing this but you need to bring in the vehical to them and have them do the testing on it ok
hope this helps best regards Mike

I would buy a gauge cluster of Ebay and do a swap. If this doesn't fix it then then follow the cable back to a module. Either the cable of the module you follow it back to is defective.

I hope this helps.