Trailer Connection - brake output and 12v aux

I’m not real hopeful that I’ll get an answer to this, but I know I’ll at least have a better understanding of what my truck SHOULD do.

2015 Tundra Crewmax Platinum, 4x4 with 5.7 with tow package - bought used in 2018 but have never towed with it.

My 7 pin trailer connection does not have 12v aux charging power.
It also does not have a signal from the brake controller (redarc liberty) through the factory harness. The brake controller has power. The old Prodigy P2 that came with the truck was basically doing the same thing, so I assumed it was the controller and replaced it.

When I connect the trailer, nothing happens from the brake controller - it should recognize a trailer is connected.
Turn, brake, reverse lights all work normally.
I also imagine that something should show up on the dash display about a trailer being connected??? Nothing happens so I’m not sure if the truck itself should be recognizing that a trailer is connected? Should it?

I checked all the fuses I could find related to towing. Is there anything else that would cause this?

My temporary plan is to run a separate brake output wire from the controller to the trailer and see if the brake controller begins functioning properly. If it does, I can also run a fused (ignition relayed) 12v power from the truck to resolve the other part of the problem. If I did this, is there anything I’d be bypassing on the truck that’s important? Any advice?

 

What does a 2015 tundra show on the dash when connected to a trailer? Anything different?

 

There seems to be an indication if using an OEM brake controller.
There's more in the manual about trailer towing.

OM34556U.pdf (toyota.com)

If that link doesn't work you can look up your manuals here.

Toyota Manuals and Warranties | Toyota Owners

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