That's dumb. With it bouncing around on the hitch guess it could be used like a relay (full on) when brake is touched. Probably an attempt to try to have one installed to work from any truck with a 7 blade hitch connector.
Still needs a connection back to the plug which then needs a connection
Looks like a cheap timer based controller. Would work the same as if it were mounted in the truck. Pretty clever way of making it so that any truck could use the trailer.
If it is an inertia brake controller it would allow brakes to work when towed with a vehicle without brake controller.
I am assuming there is a battery under the controller.
Not saying it is the right way, but at least that would make some kind of sense.
Sure... it would allow the brakes to come on for fast left turns....... MOST vehicles equipped factory with a 7 way trailer plug have a pigtail under the dash that allows a brake controller to plug right in and are pre wired for brakes
There is no good reason to do this.... IF someone didn't want to permanently install a controller and the vehicle wasn't pre wired for it, it would be pretty easy to rig up a harness to place one in the vehicle and route the wiring to the back using suction cups or whatever to secure it...
This is a clear case of someone overthinking something and coming up with a bad idea followed by even worse execution.
It hit me after I posted and I was just coming back to add that.... I'd say that would be the only 'kind of good-ish' reason to do this....
Wouldn't be a good solution at all BUT would satisfy legal requirements.... less equipment to set up/ have damaged... MAYBE even use a battery to power the brakes..... ugh... no thanks