To open the valve you need to have the ignition turned on. Press the AUTO and OFF switch at the same time and look at your display. It should show the current temp, the step monitor should have one bar illuminated and a seated figure illuminated. If so press the auto button again and the display should change to show two step monitor bars illuminated. Once that is confirmed press the mode switch until the display shows the defrost is actuated. You should have air coming out of the defrosters only at this point. Once that is done the watercock on the heater core is open and you can continue to flush the system.
