I just tackled this issue last night, and this video was a huge help. All of the other advice I have read was good, to do what Honda says and get the adjusters within the left and right lines, then the center line/cable nut thing. I did that first and it looked perfect.
I then tested it in the driveway going forward and back, switching the lever from turf to 2wd. I could feel the difference in the wheels but the display did nothing.
I then referred to this video above. I used my cycle/atv lift to get both the rear wheels off the ground and did the adjustments until the display and rear diff worked well together.
I was a bit confused as to which cable adjuster I needed to spin. I began guessing, "why am I spinning the left one?" "why am I turning the center one, and how far?" Finally the light came on and off as it should and the wheel seemed to lock and release as it should.
I'm a perfectionist and this seems like something that will drive me nuts as it is "close enough" but I don't know it's exactly where it should be adjusted. But it works.