First start with the fuses and lamps (although it is difficult for two lamps to be founded at the same time but look does not hurt)
if the fuses are fine, look with a continuity and voltage in the command of the lights and the anti -harvest relays. Since the antinieblas are lit with position and cross and go out when you change to lengths, the failure may come from there.
Finally, look at the headlight connectors to the cable, masses etc. connectors, etc.
PD looks like it is fuses.
I hope I have helped you.