4wd not working

[reg!]

Hi ! i have the push button system and when i use it to shift to 4hi or 4 low or 2hi the push button light is ok when i select one of them , the front wheel doesn't do the right thing ,with a scan it say when u are in 2hi the front diff, is engage and when u are in 4hi or 4 lo the front diff. say not engage, but when i put to auto track the scan say engage for the front diff. , and when you use the push button to switch, some time the transfer case stop to neutral, the 4x4 doesn't work and i dont know if the encoder or the 4x4 module is the problem but it seem to be possible and it cost many $$$ 1300 can.

What do u think about this no code failed?? (my usual lang is french dont care about it!) thanks ! ps:i change the push button switch but dont solve the problem...

i have 2 switch and i test those 2switch and it's supposed thats not the prob. , my mechanical man say it's the ATC module who controle the encoder ( the small electromagnet fix to the transfercase) someone know this problem ?