I found it. It is under and behind the lower left hand drawer. I pulled the drawer open and could see the crossover hose with three valves. When it comes time to use it, I will have to get the drawer out, and switch the valves. I know that I have to push down on one sides lever while lifting the other sides to remove the drawer. It did not want to come out this time, but next time it will, one way or another.