Third break light flashing

[Nathan Sloan]

I purchased my 2016 Canyon used. Upon taking it home, my brother-in-law, who was following behind me, commented that the third break light blinked non-stop whenever my foot was on the brake pedal. I’m guessing this is something the original owner programmed it to do somehow since I’ve never seen it in any other Canyon. It’s very annoying to people behind you and I would like to fix it. Does anyone know how? 

[fondupot]

Likely a harness that is installed in the wiring behind the third BRAKE light. Unscrew the the housing, pull out the wiring and see if there is something extra added on in there.