93' F-150 4X4 problem

I have a 93 model f150 with a 351 motor. The mileage is at 158,000. The 4x4 always worked well until one day the push button switch was not actuating the 4x4. I could hear the typical sound I hear coming from the switch but no louder sound coming from the front end. Also the switch light does not light up at all either. I use the truck for light work around my farm, I dont abuse it in other ways. Is there some kind of electronic part that is maybe bad? Thanks for your help, Jerry