I also am having issues with my 1999 f350 4x4. The four wheel drive just decided to stop working the morning of our blizzard. the light does not come on the dash. I changed the shift motor on the transfer case but still does not work. I checked for power at the fuses under the dash and also under the hood. All fuses test fine. I have no power at the dash board switch and no power at the transfer case. I do not have a shop manual so I do not know where to go next. Someone mentioned two moduals under the hood next to the fuse box. What are these for and should I be changing them.