86 Ranger 4X4 wont shift

I just bought a 86 ranger. When I first got it, the transfer case would shift. I push the 4x4 button, hear a little "clicking" from the dash mounted module, then a bit of a "clunk" under the seat, and 4x4 was in!
Now, when I push the 4x4 button, NOTHING! No "clicking", no "clunk", not a thing!
Tried a different module, and switch from a junk yard, still nothing! Is this the shift motor? is there any way to test the motor before I shell out 2-300 bucks?

OK, I fixed the 4X4 problem! Found a wire that should be "hot" at all times...was not.
But, now, when i'm running in 4 wheel, I hear a fairly loud "clicking" noise. All the u-joints look good, hubs lock ok, transfer case, and diff's are full of fresh fluid. (80-90 GL-5 inthe diff's, and atf III in the transfer case.) Any ideas on the noise? it's only in 4 wheel drive, not in 2 wheel.

It may be something loose inside the transfer case, my old 88 wrangler clicked when in 4 wd, and it was the chain, which had some loose pieces.