As I read my manual, automatic sway control provides differential brake control to your tow vehicle but not to the trailer. It does also apply the trailer brakes but evenly on both sides. The brake control wiring to the trailer doesn't have a left/right so there's no way to accomplish differential braking as needed to the trailer for sway control. Always use your hitch sway control to prevent or minimize sway. Then, if all else fails, you can rely on your vehicle sway control to hopefully keep the shiny side up.
2016 Rockwood Signature Ultralight 8329SS Platinum
2016 GMC Sierra 2500HD Denali Crew Cab Duramax