The large capacity washer fluid reservoir (10) is mounted under the rear seats and is filled via a hose (20) pulled out from a spring loaded reel near the fuel filler flap. The user drops the end of the hose into a fluid supply (8) placed on the ground next to the vehicle. The filling of the washer fluid can be simultaneous with re-fuelling of the vehicle. The filler hose is connected to a self-priming electric pump which fills the reservoir in a short time. The washer fluid can be heated e.g. via a heat connection from the exhaust system.