Perhaps the connector has come off? I saw it when I had a smashed rear window replaced on my FN2. Here it is highlighted
There's a connector on each side :smile3:
Just found this other pic I took from the driver's side.
i've used similar in the past - fixed the problem as good as new.If there is a slight nick on the demister it will affect the performance, if it is down to a break you can buy the following:-