>User services layer: The gas pedal, steering wheel, gearshift
>
>Business services layer: The Engine, transmission, steering box
>
>Data services layer: The wheels

Layers and crossing them is not related to components directly. Layering is architectural in nature and componentization is implementation. Although, you are correct, most components will fit into a specific layer but not all of them do.

Take, for example, and error handler object. One might put this object in the system services layer. However, if one want the error to be handled in the context in which it occured, one might put one in each layer to handle the error in that layer.