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Sounds like you have a bad TCCM Transfer Case Control Module.
The 4WD shift module is located behind the passenger side kick panel.
1. Check the 4WD shift module power and grounds.
A. Pin 2 of the C281a connector is a Dark Green/Light Green (DG/LG) wire which provides hot-at-all-times power from Battery Junction Box (BJB) fuse 13 (20 amp).
B. Pin 1 of the C281a connector is an Orange (OG) wire which provides hot-at-all-times power from Central Junction Box (CJB) fuse #5 (15 amp).
C. Pin 9 of the C281a connector is a Grey/Yellow (GY/YE) wire which provides battery voltage with the key in the Run position from CJB fuse #10 (7.5 amp).
D. Pin 7 of the C281a connector is a Black (BK) wire providing a constant ground.
E. Pin 2 of the C281b connector is a Black/White (BK/WH) wire providing a constant ground.
2. Jumper power and ground to the transfer case shift motor circuits at the shift module connection and check for the motor's ability to move.
3. Check resistance through the transfer case shift motor position switch contacts to verify that they are providing proper position input information to the module.
4. Replace the transfer case shift motor as necessary.