That would be an Ultimate ADVANTAGE I presume ? w/Spartan chassis I believe? A bit of flicker/pulsating seems to be the nature of these dashes. Mine is pretty subtle, and is more if I have the lights dimmed a bit. As you found, playing w\the dimmer knob may find a level where it isn't much. I believe some owners with severe flicker had the dash or major components replaced. I so seldom drive at night that I haven't noticed how mine currently acts.
Paul (KE5LXU) ...was fulltimin', now parttimin'
2003 Winnebago Ultimate Advantage 40e
towing 2017 Jeep Grand Cherokee Limited