Both the headlight covers of my 2000 Volvo S70 are cracked. Actually, one has a small hole which I've filled with clear nail polish. The other took a stone near the top and that sent a crack into the face of the cover. Neither seem to be taking water or interfering with the lights, but sooner or later I'll need to replace the covers. Is it possible to buy and replace just the glass covers, or do the entire headlight assemblies need to be replaced. I suspect the latter is the standard sales approach of Volvo dealers, but I'm wondering if replacing the entire assembly is really necessary.