A vehicle external mirror assembly (10) comprising a mirror head (30) adapted to support a mirror, the mirror head (30) having an external shell (36), a first foam core (37) providing support for the shell (36), a mirror base (20) adapted for mounting to a vehicle, the mirror base (20) connected to the mirror head (30) or integral with the mirror head (30) and a plurality of electrical conductors (32) disposed within the first foam core (37), the conductors (32) are arranged and constructed to diffuse stress within the foam core (37).