TCCM like a grounding issue?

I'm chasing a problem with my 1996 Tahoe (1500 4WD 5.7L) It's a Z71 if that makes a difference.

There are a few symptoms that are fairly consistent.

Radio loses power. It will sometimes flicker on and off or sometimes remain off for several minutes at a time.

This is often combined with a irregular clicking sound under the dash on the drivers side, which seems to be from the right side of the steering column but I can't be positive. It's a mechanical clicking noise like the turn indicator but very random.

My 4WD selector buttons often have no illumination and sometimes don't work. Mine has two buttons, one for 2WD and one that is split 4HI on top and 4LO on bottom.

Reading online this could be an issue with the TCCM, but I can't find the damn thing. I can't even find the part online to get a picture of it. I know it should be under the dash and I've looked up a million TCCMs, but every time I search for a vehicle specific one I get no results.

So here's my questions:

Does this sound like a tccm issue? If so, what is the part number for a replacement and where the heck is it? I understand that if it's the issue, disconnecting it would be a way to test it because that should make the radio stop dropping out.

Could the 4WD selector buttons be causing the issue if they are failing?

Could the radio be causing the problem if it has a bad or loose connection?

Is it something else like a grounding issue?