Actualy, valve is in the trunk with the tank. I will take a photo and post it. Maybe we should open a new theme for this... Under the hood there is evaporator, pressure sensor injectors connected to intake manifold (drilled into it ) and LPG computer. The switching goes automaticaly, unnoticeable, but sometimes there is a subtile twitch when throttle is released at higher rpm. Sometimes you feel switching from LPG to gas, when the tank goes empty.