Looking for this information too. I believe this would solve one of my questions with trying to tap into the dome light for floor LEDs. Not the slow fading action, just to function like the dome lights where pushing the buttons on top that normally control the dome, would control my LEDs too. I read another feed that mentioned the X1 pin 1 on the black plug. They also dropped a PDF for a 22 Denali since there were slight changes from the 21. (Attached. Picture quality is a little rough.) Of course having a 23 elevation refresh makes me a little nervous to poke around and be wrong. Hoping someone else did that nerve racking task for me.
2022 denali refresh illuminated sills.pdf