2015 prostar 6x2 question

i have a new to me 2015 prostar+ 6x2 with isx15.
Couple of questions:
What does “axle load” switch do
Also has
Diff lock switch
Off road switch
Atc off switch

Have owners manual from 2014, but has no info on tgis switch or 6x2 meritor fuel lite axle operation.

Also, do prostars have digital display for axle loading, according to manual, it should display in quadrant 1 of difital display, but does not show how to select, does it have to be enabled in programming?
Should have sensors since somehow it can load drive axle to get traction without overloading to drive axle.