Error:Datalink

Hello - I have a 2019 International HX520 in a dump truck config. It recently started showing error datalink on the dash along with nearly every other light coming on and going off at random times. CEL, TC, Stop engine, ABS, etc. I've had it to two places and they do things they think resolves it and as soon as it goes to work it pops back up. Unfortunately, I cannot take it to a dealer because it's on a diet.
Anyone have any suggestions where to begin to attempt to fix this? The truck seems to be driving fine, but the stop engine light scares me.

Thank you

 

I have not found a shop that sounds like they know how to do this. I keep getting directed to the dealer and they turn me away,

 

The tachs don't do weird things. The lights on the dash do. Almost every one of them come on, go off, beep beep, come on, go off or stay on. It's odd because when my driver came in for the day no lights were on.