OK, now we are getting somewhere.
You can take out the diff selector off the front diff and check for operation, just pay attention to what position it came out in, before you cycle it.
BTW, it is a little bit of a pain to do. you will have some fluid come out also, be prepared.
If it does not cycle when switch is engaged, when removed, you might have blown a fuse, ( this has happened before), if fuse is good then the selector is prob bad.
The diff may have gotten bound up some and since it cannot go all the way into full lock, you get no Indicator.