Typically, these types of issues are ground related. You can pull the panel at the top of the dash and access the back of the instruments. Find the ground on the instrument cluster and temporarily clip on an additional ground.
All of the instruments on your coach will have threaded rods with nuts holding the wiring on, make sure the nuts are all tight.
Don & Mary
2019 Newmar Dutch Star 4018 - All Electric
2019 Ford Raptor Crew Cab