well, on my friends 03 s-10. His low beam headlights dont work anymore, but the highs do. I told him to check the bulbs just incase, but what else could it be besides the bulbs? relay, switch, something else?

 

could be all that and or a fuse

 

Had the same problem on my old truck. Just stopped working. Turned out to be an open in the wiring harness that feeds the headlights, turn signals, cruise control & windshield wipers. Since it's the biggest PITA to get to, I had a friend at the stealership do it. Still cost close to $600(ouch). All I can say is that I hope for you it's just a stupid fuse.

 

no stupid fuse. both bulbs went. kind of weird to me, but it was a easy fix.
thanks for the help