Method for washing a windscreen of a motor vehicle by using a washing device comprising: - at least one reservoir (2, 3) containing a fluid, - a system of pipes connecting the or each reservoir to orifices through which the fluid is ejected onto the windscreen, - a pump system designed to cause the fluid to flow in the system of pipes until it is ejected through the aforesaid orifices, and - at least one windscreen wiper capable of moving over the windscreen, the method comprising at least one of the following steps: a) entrainment of the windscreen wiper from a low position to a high position, and activation of the pump system such that fluid is ejected onto the windscreen only between the moment at which the wiper is in its low position and the moment when the wiper is in an intermediate position, or only between the moment when the wiper is in an intermediate position and the moment when the wiper is in its high position, or only between the moment when the wiper is in an intermediate position and the moment when the wiper is in another intermediate position, and b) entrainment of the windscreen wiper from its high position to its low position, and activation of the pump system such that fluid is ejected onto the windscreen only between the moment when the wiper is in its high position and the moment when the wiper is in an intermediate position, or only between the moment when the wiper is in an intermediate position and the moment when the wiper is in its low position, or only between the moment when the wiper is in an intermediate position and the moment when the wiper is in another intermediate position, the method being characterized in that it comprises, after step a) or step b): - a step c) of entrainment of the windscreen wiper from its low position to its high position, and from its high position to its low position, the pump system being deactivated during this step, and after step c), - a step d) of checking the cleanliness of the windscreen, by means of one or more sensors, at least some of the aforesaid steps in the washing method being repeated as a function of the result obtained in step d). - at least one reservoir (2, 3) containing a fluid, - a system of pipes connecting the or each reservoir to orifices through which the fluid is ejected onto the windscreen, - a pump system designed to cause the fluid to flow in the system of pipes until it is ejected through the aforesaid orifices, and - at least one windscreen wiper capable of moving over the windscreen, the method comprising at least one of the following steps: a) entrainment of the windscreen wiper from a low position to a high position, and activation of the pump system such that fluid is ejected onto the windscreen only between the moment at which the wiper is in its low position and the moment when the wiper is in an intermediate position, or only between the moment when the wiper is in an intermediate position and the moment when the wiper is in its high position, or only between the moment when the wiper is in an intermediate position and the moment when the wiper is in another intermediate position, and b) entrainment of the windscreen wiper from its high position to its low position, and activation of the pump system such that fluid is ejected onto the windscreen only between the moment when the wiper is in its high position and the moment when the wiper is in an intermediate position, or only between the moment when the wiper is in an intermediate position and the moment when the wiper is in its low position, or only between the moment when the wiper is in an intermediate position and the moment when the wiper is in another intermediate position, a) entrainment of the windscreen wiper from a low position to a high position, and activation of the pump system such that fluid is ejected onto the windscreen only between the moment at which the wiper is in its low position and the moment when the wiper is in an intermediate position, or only between the moment when the wiper is in an intermediate position and the moment when the wiper is in its high position, or only between the moment when the wiper is in an intermediate position and the moment when the wiper is in another intermediate position, and b) entrainment of the windscreen wiper from its high position to its low position, and activation of the pump system such that fluid is ejected onto the windscreen only between the moment when the wiper is in its high position and the moment when the wiper is in an intermediate position, or only between the moment when the wiper is in an intermediate position and the moment when the wiper is in its low position, or only between the moment when the wiper is in an intermediate position and the moment when the wiper is in another intermediate position, - a step c) of entrainment of the windscreen wiper from its low position to its high position, and from its high position to its low position, the pump system being deactivated during this step, and after step c), - a step d) of checking the cleanliness of the windscreen, by means of one or more sensors, at least some of the aforesaid steps in the washing method being repeated as a function of the result obtained in step d).