If you have two wire at the red portion of your tail lights you should have Run, Brake/Turn, then there should be a back-up light wire.
This is how I did it: I used only one extra wire from the Dash to the rear lights.
1) Take the existing Brake/Turn wire at each Tail Light and cut it leaving a 6” or longer pigtail.
2) Take those wires and hook them up to the turn signal bulb socket on the same lights.
3) Go under the Dash, on the Brake Pedal there should be a switch with two connections, one from the battery and one going to the rear lights without power, probe the wires and find the one that has no power on it.
4) Disconnect the wire without power from the brake light sw and tape it back out of the way.
5) Run a new 16 ga min wire from the brake light sw (non powered Connector) to the rear lights.
Note - Run the wire to the rear lights from the brake light light sw outside of the vehicle first, as a test to make sure it works then go back and dress it out.
I did this but with an LED Light Setup and used the backup lights as turn signals and will add backup lights to the bumper if I ever get my shop back.
4x4, 5sp, Std Cab, Stepside, E4 Red
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