is there any way to make a material that has a bump map but no texture? because it seems that the bump map only shows through only in the places that the texture shows
Are you using the default shaders? If you are just remove the texture and your object will still be normal mapped.
Maybe I am wrong but I think he wants to simulate refraction on a windows by using only normal maps and making it transparent. Well, that's impossible. If it is transparent, you will not see the normals, unless it is only "a bit" transparent. There's a nice shader around for glass but it needs Pro version.