2006 mercedes cls320 rear demister not working

[Robbocop33]

Hi all,just purchased a 2006 cls320,rear window demister switch is illuminating on the dash,but rear demister isn't working at all.
Any common places to look?Common wire break locations?Thanks,Lee.

 

[DSM10000]

Hi all,just purchased a 2006 cls320,rear window demister switch is illuminating on the dash,but rear demister isn't working at all.
Any common places to look?Common wire break locations?Thanks,Lee.

Is there a fuse to check?