My textured quad renders fine with d3d lighting off. My quad does not render with d3d lighting on, d3drs_ambient full, and the quad's material set to full ambient. Should the quad be drawn with color? Why? Do I need to create and enable a d3dlight9? Why doesn't d3drs_ambient handle the lighting for me? I've tried rendering with normals, but do I need them with ambient lighting?

Good call... it wasn't rendering the quad at all. The problem I had was a bad render state. I was using alpha testing and had the wrong compare func. I'm not sure why the quad was ever rendering.