Ford 4x4 2002 explorer will not go into 4 wheel drive

I unhooked the battery cables and left them off for a while as I had heard might reset something but it did not help. After that and removing and testing the fuses and reinstalling them I now have a 4x4low light and a door ajar light that are on faintly all the time. Still no 4x4 action though. I will try the soft blows to the servo motor when the weather is a little better. Thanks for the ideas. The snow is over, 10 inches or so on the ground depending on which channel you are on.