4 wheel selection not working properly?

I too had the same issue on my 94 silverado truck, the 4x4 fuse good? How about the actuator switch located on the transfer case- this switch can be checked by unscrewing it, engaging the 4x4, testing it with a light tester - if this switch is bad, will not engage - also, a broken fork inside the transfer case might have broken, would need to open it up to find out though -