Just had this problem occur on mine this past weekend. Fogs, sidelamps and main beams all working fine, both dipped beams not working.
Bulbs, fuses, relays all checked and are fine. Checked continuity from fusebox to headlight plugs and all was good. But, continuity from the main headlight plug through to the connector that pushes onto the back of the dipped beam bulb is non existent.
Ruling all that out leads me to believe the wiring inside the headlight for the dipped beams is fried, so I'll be taking the headlights out tomorrow night for a closer look.
Hope this helps!