Megane windscreenwipers?

I am unable to switch my front windscreen wipers off.When the control stalk is in the "off" position the wipers still continue to operate but on the delayed sweep mode.When the reverse gear is engaged the rear wiper also sweeps across the rear window,enen though the "off" is still selected on the stalk.The only way to switch the wipers off is to remove the fuse.Is it the stalk switch unit,the wiper motor,or the ECU behind the fuse board?