4x4 not engaging
 

I have a 96 Trooper limited that will not engage into 4WD anymore. I can move the lever to 4H or 4L and it does not engage, it just stays in 2WD. tHE DASH LIGHT DOES NOT LIGHT UP EITHER. I used it 3 weeks ago and it worked fine. Does anyone have any ideas as to what I can look for or at?