do you know for a fact that both lights were running immediately before they burned out, and that they both burned out at the same time? most people don't regularly get out of their cars and check to make sure both their headlights are functioning very often, and sometimes one burnt out bulb can go unnoticed for a long time. is it possible you were running with one bulb out for a while, then the other one burned out, leading you to believe that both died at the same time?