Damaged wing mirror on Renault Trafic - can you replace just the plastic cover?

Yes. The Renault Trafic mirror is modular, so after scraping it on a gate or post you do not have to buy a complete mirror assembly. If only the outer housing is damaged, you replace just the plastic mirror cover: a clip-on cap fitted to the mirror body, available separately for the left and right side. If the mirror glass is cracked, replace only the glass insert: the insert comes out after releasing the clips, and on heated versions you also disconnect the two heater power terminals. The job takes a few minutes and does not require removing the whole mirror.

Glass insert only or insert with frame?

With broken mirror glass you have two options: a cheaper glass insert with a mounting frame, which clips in and is easy to fit, or a bare glass pane that has to be glued to the old frame. The framed insert is safer and faster. Check whether the mirror is heated and what type it is, aspherical or convex, so the field of view stays the same. Mirror covers and glass inserts for Renault Trafic are available from Transit Center.