Why are UV mapped textures rendered as black color?

Question

Actually, it is very weird, since the uv works on some model parts and not on others. It shows up in the materials but not in the render. The UV is mapping correctly to the wheel strut. The left wheel is fine, the right is just black.

There is a sun lamp and the world background is set to white.

I tried the attributes node and the texture coordinates method. As you can see from the screen shot, it does map correctly. It just won't render.

I also tried flipping the normals. Although I don't understand that part technically yet.

Since I can see it with the 3d view set to materials, does that mean that the mesh is bad? The file came from tf3dm.com . I tried the .3ds import but that one was missing parts and blown apart.

Here's the screen shot of my import and attempts.

Here's the blend file: Link to mq9predator.blend file.

Answer 1

I found the answer!

After digging around and hitting random settings on just about any button and setting known to man, I discovered the Geometry Data under the Object Data (to the left of materials panel).

I hit Clear Custom Split Normals Data and the map showed up in the render! Now to figure out what the heck a custom split normal data is...