as said here but the sensor is quite small so look at the window see where the sensor is an dput slight hole so the diode can see the light. i had this issue with rains sensors which happened to be right next too it. if not grab the maually see where the diode is or whether if you not bothered if you can pull fuse out for sensorthe sensor is behind the centre mirror chris
and they switch off/on the same way as above the RS's
sorry to butt in, but not all clios have auto headlights do they?