4WD Not Working

I have the electronic 4WD and I just found out the other day when I got stuck in my backyard in the leaves that my 4WD won't engage. I can hit the 4HI button, the light blinks like normal then it goes on steady on 4HI, but the front wheels never lock in. I switched it back and forth from 2 to 4 a few times, even tried 4LO and nothing. Weird part is when I went into 4LO i could feel it lock in and jerk the truck a little like it always does, but nothing in the front wheels.
I turned off the truck and just turned the key to start and when I went from 2 to 4 I heard the hum of the transfer case and something clunked in but the front wheels just don't go. I even tried it a few times at 20mph or so, everything looked and sounded ok but no front wheel power.

Any ideas what it could be? I'm about to take it to have it looked at cause it's out of my hands at this point, nothing I can fix, but any ideas or previous experiences would help!
Thanks!

i jost fix my i did have same thing like you but my will blow the atc fuse i went to the dealer and they check it and sed its the transfer case motor i got one for 330$the dealer want like 697$ for it its like 1 hr job go to the dealer and they have the reader for 4x4 coz my reader did not show no codes and they will tell you whats wrong or maybe your swich is bad its like 60$ or less i hope that help you or maybe your transfer case went bad

There would be four major components associated with your problem.
The switch in the dash, the actuator in the transfer case, the actuator motor, and the solenoid in the front axle.

If you feel the transfer case shifting, but the front axle isn't locking, I'd bet on the solenoid in the front axle. About $67.

T

My dash switch is stuck in 4HI and when I try to change it, I hear the actuator underneath buzzing, and there are some clicks in the dash behind the switch, but it will not switch. I checked my solder joints on the dash switch and tried to add solder to them, can't see anything wrong there.

I had an 01 S-10 that had the same problem. I found an elbow in a vacuum line under the battery that was bad. Is the 4x4 system the same in those trucks?