Thought I would share in case it helps someone else...and if anyone has a sure-fire way to keep squirrels and chipmunks from eating everything under the hood, let me know. Had the F-150 and Edge for over 5 years and they never bothered either...but after the sever cold last winter, they have destroyed all the under-hood insulation blanket, foam sound deadener around the injectors, etc...and now this...

2016 F-150 XLT 5.0 4x4. Got the message "Check 4x4" with the wrench icon. Scanner showed no codes. All related fuses/relays were fine. Applied power directly to motor and it moved both directions. Decided to pull the position sensor to test it...of course the tiny screws in the aluminum housing twisted off. Went ahead and ordered a new motor (which includes position sensor) hoping it would fix it...but it didn't.

Started tracing the wiring harness, all seemed good from the transfer case up to the firewall. Pulled the connector at the firewall and realized it wasn't as good as I thought:


Damn squirrels... ^



Unwrapped, ready to strip/solder/heat shrink


soldered, ready for heat shrink ^



connector location on right-hand firewall ^



Quick video of transfer case motor positions going from 2H-4H-4L-4H-2H:

Did a couple of quick searches for a new harness to see what they cost, but gave up and decided to just repair mine. The harness was marked gl3t-15525-db...if anyone has a price/source, please let me know.

 

Damned varmints!

The number on the harness is an engineering number, not a part number. Any Ford parts department can cross-reference it to a service part number. I've never come across a publicly accessible access to that cross-reference (so far).

 

Been there I don't know of a surefire way. I have read all the suggestions I had a problem a total of twice on in 50 years! I haven't used anything.
TJ