4wd does not engage

front wheels wont lock in? shifts into low, but front wheels still dont engage. The lights on dash work properly, no flashing or anything. When starting the lights on dash also work properly come on then go off. When put in 4wd high or low lights on dash works no flashing but still front wheels dont engage any help would be great. I hear clicking under glove box area and from transfer case, but like i said front wheels never engage. checked several fuses and the are all good??????????