Sorry bro, its is the rear windscreen? cause the front doesn't have a demister..
Anyway if its working you might be able to tell when it clear the mist....
If it get too hot and a start to burn...It might be poor electrical wiring... Guess you might have to change the demister.... :57:
Sorry to disagree Kerapu 2003, but Carens SE to United Kingdom specification does have a de-icing facility on the front screen to loosen up the screen wipers should they get iced up in winter. Something I don't think you would ever need in Singapore!! Regards