Abstract: An automatic device for actuation of components for cleaning motor vehicle glass which includes a system for detection of the dirtiness of the glass, made up of a measuring photosensitive element receiving light directly through the glass and a reference photosensitive element isolated from any direct light and influenced only by the light transmitted through the interior of the glassing and an electronic circuit to receive and compare the responses of the two photosensitive elements and means to control the cleaning components automatically when the difference is response of these elements exceeds a certain threshold.