You have the lights cross-wired. IIRC, a tail/brake combination LED fixture has 3 wires, red/black/white. The white is usually ground, the black tail and the red brake. Some manufacturers do not follow this and mix the black and red, or do their own thing entirely!!
You can test this with a 12VDC battery. Connect the white to ground and touch the black to positive. It should light. Notice the intensity of the LED. Then remove the black and replace it with the red. It should get brighter (brake). If it's the other way around, you still know which wire from the LED is what.
It should be a snap from there. Just match it with your trailer wiring and you're good to go!
The green on your A/S is probably ground, and you'll have to test for the tail and brake with a test light.