For years I have dealt with this issue and chased forum answers to no end. I gave up trying to figure this out and then suddenly...It just started working again after 3 years...then stopped.

THE INITIAL PROBLEM:
The indicator dial stopped lighting up (the amber light to show which mode it was in) about 5 years ago and was randomly on some days...and not on others. Eventually, it just stopped coming on except maybe for a few days every 6 months or so.

WHAT I HAVE DONE TO TRY AND FIX IT:
1: Took it to dealer and they said I need my transfer case rebuilt. I argued with this because it worked fine when the electronics worked. They talked me into a $1500 rebuild and guess what? Didn't fix the issue.
2: I have replaced every single ground wire and battery wire I could find through forums, youtube, manuals, etc. All but the column ground wire that I just found out about. No change.
3: I replaced the TCM and had it programmed "under hood, not in the TCCM". No change in the issue.
4: I replaced the selector dial in the dash. No change.
5: I spent 2 days, about 5-6hrs a day tracing and testing every single wire in the harness to the TCCM to the motor in the transfer case and to the TCM. I checked for ground from the connector to the chassis. Everything was fine.
6: Removed and tested the transfer case shift motor. Tested fine and has always worked fine when everything else works.

THE MOST RECENT PROBLEM:
So, our temps dropped from the 60s to the low teens overnight and suddenly, after not working for almost 3 years now....I notice the indicator light was on the dial in dash. I cycled it through all the 4WD modes and it worked perfectly. However, something new has happened. When I start the vehicle, the dial does not "boot up" and is dead...until I put it in reverse or in neutral or in drive. Then the dial lights boots up and I can use it. Before, it came on when the vehicle started. My mind wants to go back to a ground wire issue or something because it only wants to work when it is cold...Yet, I have replaced and tested all the ground wires. I have checked all the fuses. Today, it's back off again and hasn't been coming on for 2 days (again).

I am stumped here.... I was thinking maybe it is the TCCM (in dash) but I have not been able to find that particular part number ANYWHERE for sale. I am getting power to the TCCM but the code says that it is not communicating. Even though harness is tested. I know this, I am about $2,000 invested in this over the period of about 5 years and easily 30+ hours screwing with it....only to have it randomly work perfectly fine when it gets cold...or just when it wants. I have search forums like you wouldn't believe on this nightmare and have not found ANYONE with this randomly works issue...