Trailer brake lights stuck on.

So I followed glad hand lines and they go to that valve. There is no valve at the port but a small 1/4 orange line leading off. I followed it and it went up in the dash to a bank of sensors. I unplugged the sensor going to the orange line and the lights stayed on. Had 12V going to sensor. Tested continuity at the sensor and it was O.L and when I applied air there was no resistance. Sensor is good.
What else can I check?

I need a wiring diagram and maybe my freightliner dealer would be kind and give me one but would any of you have one you would be willing to send me?

 

So I followed the wiring for the trailer all the way up to almost behind the cab and when I disconnected it there the lights went off and I tested power there and found that I have 12 v going down the line to the trailer brake light wire. So I know that the truck (Or stray wire) in the front of the truck sending power back.

 

Swapped them and still the same issue.

 

they go out

 

They are always on when key is on and I can feel the relay clicking when removing/installing it.

 

correct, truck brake lights work fine.

 

Another thing is when I pull the relay the ABS valves on the trailer do a quick check and click a few times just on the trailer.