If the cable is stuck you wont be able to squeeze it or it will be very hard to move it much at all. Have the front end off the ground so that if you have to spin the wheels a little to get it to engauge you can.

 

My 4X4 went out same as his one night it worked the next morning it didnt. I have a 1990 s10 blazer. It does nothing when I change out of 2hi. I tried to pull the cable from the actuator to bypass it but still nothing. Does anyone have any clue what might be causing this? I am currently putting whole new suspension and it would be easy to fix 4X4 while its apart. thanks in advance for everyones help.