Rpm gage not working properly.

[petit]

I've got a 2006 dodge 3500 diesel 5.9 I've been having a hard time starting it so I went had had my batteries chevk found one had a dead cell so I replaced them both now for somereason my RPM gage is not working like it should when I start it it only shows it idling @300 rpm sometimes it shows 100 rpm going down the highway it's good I cleaned all the battery connection but still the same dies anyone have an idea on what I need to do or check?

 

[18CrewDually]

Sounds like typical cluster. You could disconnect your batteries and remove the cluster to send it to a repair facility such as Circuit board Medic or there is a quick fix you can try yourself. I'll message you the link for directions.