I am certain someone has had the same issue as I am having, but was unable to find anything on the forums with this issue.
My 2012 Nav 2.5 LE has no problem engaging 4hi, but does not under any circumstances want to shift over to 4lo.
What I have checked so far :
Tested transfer switches, it has continuity when pressed and vise versa for the others
Tested relays, it switches current when power supply is attached
Did the "peddel dance" with no fault codes
Tested ABS sensors and all seemed ok
Front wheel bearings is also good
Transfer control unit was replaced without success
All im left with to my knowledge is to fissically trace and test the wires.
Any advice from the gurus will be much appreciated