sometimes my headlights work sometimes they don't. changed the bulbs a few months ago. sometimes when i turn on the high beams they go off. sometimes they won't even turn on. Checked the fuses too.

 

Possibly a faulty switch, try a short spray of WD40 into the switch.

 

I had this problem in my car, however, somebody backed into it a few days afterwards and cracked both the headlights, we reran the wires and haven't had a problem since. But like britishdude said, it could be a faulty switch, faulty wire or connection. If none of these work you may want to make sure the system is grounded properly as well. Good Luck.