1997 Expediton 4wd problems

I have a 1997 Ford Expedition 4wd. When I turn the switch absolutely nothing happens. I assume it is an electrical problem but I was wondering if anyone knew of any common problems with this. Thanks in advance

I had the same problem with my 97. Took it to a tranny shop - they removed the shield at the front differential, freed up the linkage with some WD40, and $40 bucks later, I had 4WD.