On a 7-pin coach hitch connector, the five o'clock pin is assigned to the "trailer electric brake controller." (See "7-way RV Standard" at this link) The operator manual for a 2014 Via shows a 7-pin connector and says:
The trailer brake controller connector is located beneath the driver seat.
That gives you a path from coach bumper to dash.
2008 Holiday Rambler Admiral 30PDD (Ford F-53 chassis)
2009 Honda Fit Sport
Thanks. I saw the etrailer information too. The problem-where in the dash do I find the brake controller plug/wires. I checked all the Winnebago chassis wiring diagrams and nothing. I also tried to find the MB Sprinter wiring diagrams with no success. I ended up spending a couple of hours running a wire so it is done.