Symbol 1866 from ISO 7000 - Title/Meaning: Ventilation air flow, lower air outlet Function/description: To identify the control that allows air to flow from the lower air outlets. To indicate that air is flowing from the lower air outlets.
Additional information: 
On road vehicles: arrow may be coloured blue to denote cool air or red to denote heated air.
Own work using: iso.org/obp/graphics/grs/cc98c832-613c-4963-9420-d59a46ba037e 200.png
Vectorization:  Mrmw