2001 f150 serious electrical problem

[adrenalin2k4]

I have a 2001 f-150 5.4l 4x4 automatic. I have been working on this truck for about 3 months trying to fix this electrical problem. The wipers don't work, the windows won't roll down and the shift on the fly 4 wheel drive doesn't work as well. I have changed the wiper motor, the GEM module, the cab fuse box, the battery terminal ends. Plus I have checked all the inline fuses, the relays and all the other fuses in this truck. The only thing I haven't changed is the engine compartment fuse/relay center, the security module or the ignition switch. If anyone has any ideas? Please help! I really don't know what else to do. Thanks in advance.

[65comet]

The 4x4 engage could be a separate issue. When my 98 150 or 05 Expedition have had electrical problems I've searched for electrical diagrams for the related system. Then followed the hot wires from the fuse panel out with a meter till the power was lost and found the problem. Electrical is always a pain in the butt.
You can also try this other specific forum for that series of F-150.
http://www.f150forum.com/f6/