Abstract: A liquid application system particularly adapted to being employed in motor vehicle washing is disclosed. The system includes a manually actuable liquid applicator and a supply subsystem which supplies liquid under pressure to the applicator from several discrete liquid sources. Sequencing control so as to achieve a supply of liquid from one and then another of the sources is achieved by sensing a pressure condition within the liquid supply, such as, an increased pressure which occurs within the liquid supply system when the applicator is changed from its operable mode to its inoperable mode. Valving control is then achieved so that fluid communication is cyclically established between the one and another liquid sources in response to a cyclical change of operation of the applicator between its operable and inoperable modes. In such a manner, by merely changing the applicator between its operable and inoperable modes, one can effectively select a particular liquid supplied to the applicator.