If you follow the owners manual you will have excessive current draw and kill the battery.
The only way I found to get around this without running a dedicated charge wire from coach is by installing a momentary switch under the hood that is connected to the park signal from transmission shifter assembly.
This was done on a 2011 Lincoln MKX with push button start.
Tap into the park switch ckt. Located on passenger side of floor console. pull off side trim. The wire you want is Green located in pin 8 of the largest connector on right side of console.
Run this wire to a momentary switch to ground underneath the hood.
When towing place vehicle in neutral and shut off, open hood and close all doors. At this point dash will display "Shift to park" until momentary switch is pressed. press switch and shut hood. dash should go out and draw on battery will be eliminated.
This has to be done with a momentary (push button) style switch. If it is done with a switch that can be left on it will be possible to start the vehicle in gear.
I am not an engineer and except no responsibly for negative effects of this alteration
