So I found the trailer brake wiring ring under the hood, and connected it to the correct large terminal in the underhood fuse box.

When I put in the correct size 30A fuse and went back into the H2 the brake controller was already on.

Hmm ok now does it automatically come on when the doors are opened or something I thought at first.

When for a quick trip around the block, and shut the Hummer off.

The trailer brake controller stayed on even after opening the driver door, which normally turns everything off.

I just disconnected it for tonight so it wouldn't drain the battery.

I admittedly did NOT read the manual for the brake controller which I am doing now.
Its the tekonsha P3 BTW

 

Ahhh the P3 does indeed have power buttons, will give that a go tomorrow