94 explorer 4wd problem

No solenoid. There is an electronic shift control module over the left rear wheel well, with it's ground nearby. As usual, before jumping to expensive conclusions, check powers and grounds thoroughly. Interior fuses 7 and 13(17 if it's an electronic dash), fuse 7 @ power distribution box Grounds at the shift module and left cowl. Check switch for continuity. Try this: Raise and support the truck wheels off the ground. (Safety! Safety!) Have a helper cycle the switch while you are underneath rapping on the shift motor, just like we used to do on starters. There is a set of contacts under a cover on the shift motor which dry up and get corroded, especially if it doesnt get cycled regularly. The cover is held on with (I think) 3 tamper proof torx screws, and if you pull it make sure to index it. Good luck, and happy hunting, Ben

I redid my shift motor three times. After the last time it stopped working I just bought a new one. The internal stops inside the motor are poorly designed and it over-runs and jambs. Hopefully the new one (aftermarket brand) has better designed internal stops. I think it was less then $125 for the new motor and gear head.