Brake lights at Berlingo no longer light up

Hello! My wife was last approached because of her brake lights on her Berlingo1,4 (Bj2002).If you satisfied the brake, it does not light up.Since both lights do not go, I had thought of the fuse.In the fuse box, however, no fuse was burned.From the manual I could not find the fuse belonging to the brake lights either.But I also looked for the lamps.My wife had made her TÜV at the Citroen contractor at the beginning of the year and there the brake lights would also be criticized (I’m not quite sure now, because on the Rep. note only lamp was replaced).When I checked the lamps, I had to find out the one lamp even missing. I then installed two new lamps, but without any success Since I don’t trust the dealer quite over the way, I try it here times.Maybe someone has a good tip. MFG ADI