I believe they should all be lite up when the batteries are full.
As the charge drops off less lights will be lite up.
How it has /does work on all mine.
2002 Monaco Windsor 40PKD. Marjorie 2.
2015 Equinox V6 Roadmaster tow setup
1996 Fleetwood Bounder 36S P32, Sold Oct. 2nd, 2020. Yay.