main brake lights don't work, third does

[Jinster]

Hi everyone. My main brake lights have stopped working. I am not sure for how long now. The third brake light up top still works. I've already replaced the brake switch (which couldn't have been the problem anyway if the third brake light worked).

I have taken out both rear lights and put 12V to the brake bulbs and they work.

Not sure how to proceed from here now. Anyone got any suggestions?

[pilot4fn]

Starting from simple route - you have probably cheked the fuses already (could the third brake light have different fuse...)