Headlights

It is not impossible that both bulbs are bad. I have had it happen. you can test for power at the light plug with a tester. turn on the high beams and see if you have voltage at the plug. if you do then it is likely the bulbs, if not then check all fuses and relays associated with the lights.

and yes, it can be the dimmer switch, check the other stuff first.

Dimmer do you mean hl switch or the million dollar module

check high beam fusesfirst