Don't think my 4x4 works.

[Pnutman]

94 B4000 4x4.
Dont seem as though the front wheel hubs are engaging. When I press the button on the dash, the (yes Elizabeth, they are automatic hubs) the 4x4 light comes on but I can't feel anything steering wise that indicates engagement. I pulled the front hubs, then started the truck and engaged the switch. I hear a clicking sound. I don't see the axle shafts move. I can still turn the shafts by hand with the truck running and 4x engaged. The rotors still turn by hand too. I put the hubs back on, and I can still turn the rotors by hand. I looked up on the axle housing but cannot locate a solenoid or other switch, vacum or electric. Where is it and how do I test it? New info: I think I just found out that I have a Borg_Warner transfer with electric switch (since I got an electric button) How do I test that dohicky on the back of the transfer?