It's the 2 wheel Hi versus the 4 wheel drive Hi and Low. I have 2HI, 4Hi, 4LOW, and AUTO 4WD buttons for the 4 wheel drive system. The 2HI button light is on some times and off others. In the readin the book it looks like it should be on, but I'm not sure.I just bought this vehicle and there seems to be a lot of things I don't think are working like they should.
Mine stays on when 2Hi is selected. You may want to ask the dealer about it. You may also try running on Auto for a while and 4Hi for a while. You don't need to run for very long. The servos need to be actuated from time to time. If you run in 4Lo, do it only on grass or driving in a straight line, no turning. 4Lo is intended only for off road where the tires can slip. Actuating the servos and rocking the switches may help the light blinking on and off.
I drive in 2Hi most of the time except in winter when I will switch to Auto. Running in 4Hi is hard on the drive system on dry roads when making turns. I've found that the Auto mode switches the 4WD on fairly quick.