Unknown button

[Pickledmum]

Hi all,

recently bought an estima areas 2012 model and just wondered if anyone can tell me what this button does? It’s a rocker button that looks like a cloud with rain and a red light on it at the bottom. 
 

many thanks

[flash22]

rear fog light that was fitted for the IVA/MOT when it was imported, the switch was fitted 90º out

eg.

https://www.ebay.co.uk/itm/204302291272

[Paulscarbs]

It certainly makes me question that, if the importer was unaware of the correct orientation for the switch, what else was omitted from looking after the vehicle before the customer accepted the keys!