2011 ford fusion no working tail lights?

Brake lights and turn signals work. Bulbs have been changed and all known fuses have been changed… What could be the problem

You may have mistakenly installed the wrong bulbs.
Let me explain.

Certain bulbs, especially on cars, have TWO filaments in one bulb. One filament is for running lights at night and the other filament is for brakes.

They even fit the same socket. You can check by removing the bulb and look for TWO filaments. If there's only one, then that's the problem.

The 2 types are NOT the same, a single filament one has 2 pins opposite each other on the base, a 2 filament has 2 pins offset, so the 2 types can't be mixed (they hope). But heavy- handedness often forces a single- filament into a 2- filament socket (or vice versa).
You could have a fault in the taillight switch section of your light switch, or a broken connector or wire.
Take it to an expert.

Check the switch located behind the brake pedal its attached to the arm where the foot pedal is look under the dash and you will see it just above the foot pad sometimes they get gunk ed up and can be cleaned but i myself would get a new one