Working on a 2021 that has incandescent taillights. It has 3 bulbs: lower is backup (3 wires to socket, single filament), Center is turn (3 wires to socket, single filament) and top brake/tail (3 wires to socket, dual filament). I need diagram defining the colors for installation of a flat town light system. Tons of info out there on LED but the 3 bulb setup is sparce. Thanks for any help.

Follow up: It appears that turn has two black wires and one orange. Stop/tail has black, blue, yellow. Are all black wires ground?

 

You mean this?

https://www.etrailer.com/static/imag...onal_2_500.jpg

 

I am setting it up to flat tow behind a motor home. I need to splice into the taillight wiring and route to the front of the truck so the trailer lights connection from the motor home connects to the rear lights on the towed Ranger.

 

I'm confused. You've identified the wires you need to connect to, but now need a schematic to identify the wires you need to connect to?