Cracked cold solder joints could be the issue for a flickering HUD, or center display.
My Vibe radio had half the display flickering. Took it apart, hit all the solder joints with my iron and it is fixed. My Corvette, if it had ACC, also has the same thing happen to the units as it gets older.
I learned about cracked cold solder joints from working on my pinball machines. Most of these joints are large enough to see the crack, but not always. Over years of heat and cold down cycles, these joints crack, causing issues like these. A sometimes on, sometimes off, problem shows up, like a flickering HUD. Simply hitting each joint with a solder iron, reflows the solder and melts the crack back.
For auto repair, you must take the units apart and get to the printed circuit boards to do this though.
