AC symbol flashing, why?

[blackturbo]

May be a silly question but my AC button has decided to start flashing as apposed to being on constantly?

Any ideas why?

Cheers

 

[Ruddmeister]

cos the outside temp is below about 3deg C and the aircon stops functioning to protect itself from Ice

 

[blackturbo]

Lol clears that up! Cheers