The graphic has never shown that my car is in 4wd, it only shows the front tires illuminated. I have gotten stuck a couple of times, in my own drive when I was trying to make it go into 4wd. (it never did, had to be dug out). Does your back tires on the graphic light up?
How do I know if 4wd is activated? on 2007 Mercury Mariner Hybrid