They have a recall on those, double check and make sure your's is not part of it. Now, to fix this problem, bang on it a few times with a hammer, while someone plays with the switch. But do not hit the plastic part, oh god.. don't hit the plastic. be careful... but hey, this will fix your problem. :)
If it is electrically actuated try getting out the trouble codes (DTC) with a dealer. On older Chevrolet Blazer S10 Models the shift motor/encoder gets stuck and lets you shift only from 2HI to 4LO as an emergency program. Replace the motor/encoder.
When not used, they do get stuck and hard to shift. I had this with my 93. I put it in neutral and forced it into 4 wheel low. After it went, it is now easier to shift into.
You have to be stopped with the transmission in neutral when you shift in or out of low 4 wheel drive. Park doesn't work as neutral. When you push the rocker switch up for high 4 wheel drive once you will be in high 4 wheel drive, push it again for high 2 wheel drive, you can shift between high 2 and 4 wheel drive while you are driving.
I have a 4 wheel drive Chevy Blazer 2001 that got stuck in 4 wheel drive, the only way I got it out was to put it into neutral and switch the 4 wheel drive button. It worked!!
Shift it on 2H, then "REVERSE" for about 10 to 15 Feet....
One possibility is the shift rod in the steering column may have broke, that happened to my 93. The shift lever wouldn't move, that is what led me to believe it was the shift rod.
Take transfer case apart its stuck I'm doin it right now
Make sure your brake lites work.If they dont replace brake lite switch
why is my 2006 Nissan altima gear shift stuck in park
your shift solenoid a is stuck open in your tranny time for a gagage visit
If you are no longer able to shift, then it's possible the linkage is broken. If this is a periodic problem, you may need to adjust the linkage or shift cable so that everything is prooerly lined up
take it to get fix