I put a hitch receiver light in my 2016 lariat that plugs into the flat 4 wire, when it's dark I have no problem with it but during the daylight several messages pop up ie: trailer disconnected, right bulb not working, left bulb not working and a couple others, does anyone know the solution? truck has max tow package and radar tails if that makes difference, my other concern is does that being plugged in tell my tranny to go into tow/ haul mode? any help?

 

You might want to read the manual. Owner.ford.com

To solve the problem, unplug the light, a d the truck won't think a trailer is connected. Lights can be hooked up via a run from the battery. Discussed many times in the forum.

You are likely disabling your sensors also. All in all, a bad idea.

And nothing changes the truck to tow/haul or any other mode automatically.