mlwarrenatc

I have a 2003 TT Roadster. Car is reporting an issue with the brake light (passenger side) when I turn the lights on. Checked it out and saw both of the passenger lights were out. The turn signal and both brake lights work. I do know the brake lights have 2 filaments. I was thinking the filaments that turn on when the lights are on may have gone bad. I tried replacing the bulbs and it still did not work. Is there any way to tell if it's a short in the system or with the brake light assembly itself? If it is a short in the wiring does anyone know the expected cost to get this fixed?

Any input would be appreciated. Thanks!