Transmission problems for a 1995 chevy silverado

I have a 1995 silverado z71 with auto transmission. When ever I go to put it in 4wd (floor shift) it will cause the fuse to blow and will not engage. What is wrong with it and what can I do to fix it? Does it have sensor that needs replacing? If so where is it and can I relace it myself? Please help!!!

I have a 1995 silverado z71 with auto transmission. When ever I go to put it in 4wd (floor shift) it will cause the fuse to blow and will not engage. What is wrong with it and what can I do to fix it? Does it have sensor that needs replacing? If so where is it and can I relace it myself? Please help!!!

Check the actuator motor and wiring on front Axel for short or bad wiring.