The
Invisihitch Trailer Hitch I installed on my vehicle includes the BMW trailer module and OEM wiring connections to fully integrate into my 2015 X3.
The wiring for my hitch includes a
7-Pin USCAR connector that feeds the
US-standard 7-Way Round Socket on the vehicle exterior, that accepts the trailer connector.
My wiring harness is fully polulated, except for the blue brake wire, for the electrical brake controller module used on larger trailers.
My wiring harness does have the always-on +12V battery power wire, to provide power to the trailer.
This Invisihitch system (for your model year), or the corresponding BMW OEM hitch system, would provide +12V continuous power to the connected trailer.