Ive got this posted on another forum so sorry to bore you if you have seen twice.
I was filling my window wash water up in the car and having a general look around when i noticed this:

The black thing like a plug was not in the hole so i popped it in
It was located here just right of the engine mound.


Does anybody know what it is?
Should it have been plugged in? or left out?
Any ideas?
Thanks yummy
