If your lows do not work at all before you do anything make sure your both low beam bulbs are not blown out. My freinds car had this happen and he replaced both bulbs and they work now. Next check the fuses. There is a tester you can buy that has needle tips so you can poke the wires and see if you have power getting in the wires. You poke the black into the ground wire and red in the power side..
There are also head light relays you might want to check also.