On this parts fiche the Headlamp Assy is the most specified component.
The most reasonably priced component used on the Lt-f500f Quad Runner 4wd 2000 (y) Usa (e03) Quadrunner Quad-runn Headlamp (model Y/k1/k2) is the Washer.
Some items from this specific schematic: Reflex Reflector,fr Side, Headlamp Assy, Bulb 12v 30/30w, Washer.