If the Headlamp fuse is good (power on both sides) & you have varified Voltage in & out of the switch, then it would have to be:a) Groundb) Head Light bulbsc) Wiringd) Plugs at Head Lights
I would want to double check Voltage into the Switch with a Meter & at the Head Light plugs.
Your post was:<< Headlights, brights and dims won't work,>>
So if you are holding the Light switch to "bright" & the lights come on, then the Switch is still bad.
The Diagram I posted, shows there is no other components connected. The flow goes thru the Multi Function Switch.Verify Voltage into switch & out with the switch in Low Beam position.