I have a (new to me) 2011 Honda CRV EX and there is a button that I can't find any documentation for. The placement of it is driver side, about knee level and farther down than the VSA and mirror position controls. It is a tri-state button: pressed down a small light illuminates a light with an icon of a single squiggly line (almost like a defrost symbol). In the middle is the off position. Pressed up it illuminates a light with an icon of a double squiggly line (almost like this is "high" and the other position is "low"). My best guess is it might be heat or defrost on the side mirrors, but according to documentation that is typically a center console button with the rear defrost. Mine isn't equipped with that.