I've been looking through threads about this issue and there's plenty but all the ones I check don't have any solid conclusions. Here's my issue:

I have a 2001 F250, 7.3L with the auto/manual hubs and the 4wd dial on the dash. The other day I tried engaging the 4WD but it would not engage. My hubs have not seemed to work on auto very well so I usually turn them manually. I did this and still nothing, no light on the dash. For a while now when it was working I would hear a high pitched squeak or squeal until the 4WD engaged then if I was in and out (using the dial) it was fine until it sat and got cold. We got some snow the other night and I decided to check the fuses as I wanted to use the 4WD. I checked both under the dash and under the hood, nothing blown. When I got back in and used the dial the 4WD came engaged (hubs were turned to manual) and the dash light showed 4X4. The truck sat overnight with the 4WD engaged (I live one a farm so my driveway doesn't always get plowed). This morning when I went to use it the dash light, 4X4 was off even though the dial was still in 4H. Squeal still present when starting out, turned the dial to 2H and the 4WD wouldn't disengage. Turned the hubs from manual to auto, nothing. Drove backwards for a ways, pulled both fuses again (still okay), played with the dash dial some, no chages. Nothing seems to be working and the system is still in 4WD. I haven't noticed the defroster staying on all the time but it's winter and i only use the defrost or foot and both work fine. I'm suppose to drive to Omaha Sunday and would, at the very least, like to have the 4WD disengaged. Any help would be much appreciated.