My tail light on the passenger side is not acting properly. When the tailights are in the on position, the end light, which is the tail light and the brake light, lights up as if the brakes are on.

When the lights are not on and you step on the brake, this same light lights up as if the tail light is on, not the brake light. I have tried moving the wires around to see if they are incorrect, but am not having any luck. I replaced the circuit board, so I don't believe that is the problem. Thanks for any help.