No need for a switched circuit. A RedArc has a position/inertia switch to activate. And a dial to adjust sensitivity. Good unit had it on a truck. New truck's is built in, but the RedArc worked great. Istall was stupid easy too.I pull a 7000# dump trailer with a M7060. I've thought about adding a brake controller. I have an automotive style 7 pin connector.
There is no brake wiring on this model. North America, in general may not have brake wiring on tractors.
What I planned to do was get a simple controller with a slide/hand spike, and just use that to activate the brakes. It should be simple 1 wire to the connector, plus the 12v to power the unit.
I've never felt the need for it except in winter. I tow on highway, as fast as she'll go.
Whatever you do, tow on the drawbar, not the 3pt with one of those adapters. Some will chain the 3pt hitch down if they do. That would likely be fine but subject to failure and forgetting.
I had a 2" receiver adapter made up to put over the drawbar to use a truck hitch and ball.