Need some tips/ help vnl 770 Drivers digital display problem?

2000 VNL770 N-14 and Eaton 1st gen auto shift 10 spd.

the digital display on left side of instrument panel lights up,( backlight) but does not display any characters/ text menu ect? when I use the "stick" to run thru the menu's, I can get it to do a dash gauge test, and light test, etc. But nothing is on the display. I replaced the digital display with a new unit, and still nothing..
I have checked the inside of the entire instrument panel with a magnifying glass for issues of the solder joints being broken- and cannot find any. All the gauges work and act normal.



Pablo? you think this might be a data link cable problem? Vehicle computer module issue?? any ideas on where to start looking?

I have a multi setting soldering heat gun- shall I try it to make sure all the pins are soldered on the entire board again?

It would be handy if the menu/ display would work, =o)