I'm not sure on a 01, but later vehicles, the ecm, bcm etc, sends data to the gauge cluster. So if your data bus is not communicating you will have no gauges.
Did they just legalize deletes? Will our tuners be able to start up again? My 2018 is finally out of warranty, so i would like to do some egr and DPF preventative maintenance.
Are you plowing with tow/haul on? That makes it charge higher. And the load from plow lift can be a pretty big drain. Hopefully you have the + side of lift on one battery and the - on the other.