I am setting up a simple scene with only a single object, a truck, and a point light. It seems that regardless of where I put the light, the hood (among other portions) of the truck won't be lit. Here's an example:
My first thought was that it was a problem with the materials on the truck. But the material on the hood is the same as that on the top and sides, so I don't think that it is the issue.
I also replaced all of the materials with the default one (diffuse intensity 0.8 and specular intensity 0.5) to see just the contribution from lighting more clearly:
Is there some other reason that might be making it impossible to light certain portions of the object?
Other possibly relevant information: In the images above, the light is a bit above the driver's seat of the truck, but the problem remains even if it is directly on top of the hood. I have had better luck with Hemi lights, but would prefer to use point lights if possible. I am using Blender Internal rendering. I am also happy to post more images (the car rendered with shadeless textures, the actual blend file, etc) in the follow-up.