I finally got around to metering mine out and the pink wire shows 12 volts on it as soon as you turn the truck on.
The red is constant 12 volts, the green goes to the bumper for trailer brakes.
Now the black wire should be ground but I measure 1.7 millivolts on it when the truck is off and 5 millivolts when the truck is running. I had my meter grounded to the chassis. When I checked it between the battery negative terminal and that black wire I read 4 millivolts with the truck off and 10 millivolts with it on.
I do see 12 volts from the pink to the black wire when the truck is on but that black wire does not go directly to a chassis ground.
I do not see any of the wires on the 4 pin plug change when I step on the brake peddle so there is no way the DrawTite adapter can work.
I saw another post here where someone used the three wires as they are and used a separate wire to trigger it from the brake pedal so I'm wondering why I see that small random voltage on the black wire.
It appears that Dodge have definitely changed their wiring for 2013.