A device for washing a surface of a motor vehicle part , the device comprising: - a water pump for supplying water from a water source to an air-water control valve ; - an air pump for supplying a flow of an air from an air source to an air-water control valve ; - at least one water outlet for supplying water from the air-water control valve to the motor vehicle part ; and - at least one air outlet for supplying air from the air-water control valve to the motor vehicle part , wherein the air-water control valve comprises at least one water channel and at least one air channel separate from the water channel , wherein the air-water control valve further comprises a valve member configured to be driven into a closed position closing the air channel when water flows through the water channel with a water pressure (PA) higher than a predetermined valve member pressure (PV) plus an air channel pressure (PA') or into an open position opening the air channel when no water flows through the water channel or when water flows with a water pressure (PA) lower than the predetermined valve member pressure (PV) plus the air channel pressure (PA'), and biasing means for biasing the valve member for closing the water channel , wherein, in use, the water pump and the air pump are operated such that water is allowed to flow through the air-water control valve to the surface of the motor vehicle part while air is prevented from flowing through the air-water control valve , with the air pump in operation while the water pump is shut down such that no water flows through the air-water control valve and an air burst is supplied to the surface of the motor vehicle part , characterized in that the valve member is a membrane made of rubber or any other similar material capable for opening or closing the water channel and the air channel when deformed depending on fluid flowing through the air-water control valve . - a water pump for supplying water from a water source to an air-water control valve ; - an air pump for supplying a flow of an air from an air source to an air-water control valve ; - at least one water outlet for supplying water from the air-water control valve to the motor vehicle part ; and - at least one air outlet for supplying air from the air-water control valve to the motor vehicle part , wherein the air-water control valve comprises at least one water channel and at least one air channel separate from the water channel , wherein the air-water control valve further comprises a valve member configured to be driven into a closed position closing the air channel when water flows through the water channel with a water pressure (PA) higher than a predetermined valve member pressure (PV) plus an air channel pressure (PA') or into an open position opening the air channel when no water flows through the water channel or when water flows with a water pressure (PA) lower than the predetermined valve member pressure (PV) plus the air channel pressure (PA'), and biasing means for biasing the valve member for closing the water channel , wherein, in use, the water pump and the air pump are operated such that water is allowed to flow through the air-water control valve to the surface of the motor vehicle part while air is prevented from flowing through the air-water control valve , with the air pump in operation while the water pump is shut down such that no water flows through the air-water control valve and an air burst is supplied to the surface of the motor vehicle part , characterized in that the valve member is a membrane made of rubber or any other similar material capable for opening or closing the water channel and the air channel when deformed depending on fluid flowing through the air-water control valve . <EOS>