Wont let me upload a pic so on my 03 wrx waggon below the temp controle *** there is a tiny air vent 4 little slots 20mm x 2mm and they have a pipe comming off it.
was having a look at back of radio today and seen it and now its bugging me as to what it is and for.
Thanks

 

I could be wrong but I believe it's for the temperature measurement for the feedback in the air con/climate control system.

 

^^^^^^^^^^^^

The pipe is called an
Aspirator hose, 73444FG000