Just took delivery of Kitchenaid French Door Bottom Mount Freezer. Have existing waterline from previous fridge. Instruction manual says to remove the black nylon plug from the grey water tube. All of the tubes on the back of the fridge are connected to something and the manual doesn't explain which grey tube to disconnect in order to remove the black nylon plug. Once I find that, I'm good to go as far as hoking up the water line. Can anyone tell me which grey tube? There are 3!