you have not said what dammage was caused by the drop? sounds more like a brocken wire in the loom, is it the front or back that does not work? if it is both check the earth, if it is just one that is not working the other should flash fast, which would say a live fault or bulb. would not think it would be switch unless the switch was dammaged during drop, if swich is on the side that hit ground.