Retrofitted standard vehicle side mirror

The light body insert (400) is inserted retrospectively into a standard vehicle side mirror whose body is fully externally closed. The light body insert is in the form of a one-piece shell for insertion in shape-locking manner into an aperture retrospectively made in a continuous wall section of the mirror housing (30) and has at least one light source (420). Independent claims are also included for the following: (a) a kit for fitting a production vehicle side mirror with a flashing light body (b) and a method of retrospectively fitting a production vehicle side mirror with a flashing light body.