Where is the water valve of Mercedes gl400 heater?

Between the main engine water tank and the warm air water tank. Mercedes-Benz gl400 heater water valve is located between the main engine water tank and the heater water tank. Mercedes-Benz refers to a luxury car brand in Germany. Mercedes-Benz Automobile Company is the oldest manufacturer in the world, which is famous for producing high-quality and high-performance luxury cars. It is also one of the top ten automobile companies in the world.