[madeforeachother]

We just got our new trailer and the manual says nothing about the tank heaters and figured it best to ask my MOC family about them. The control panel has every switch labeled except the three switches with one label above the switches saying tank heaters. My questions are; left to right, what switch controls what tank and it's heater? Second question is; I have four tanks,fresh water, galley, grey, and the ever popular black tank. Why only three tank heaters? If anyone could help us with this, we would very much appreciate it. The service department at the dealer is not very helpful.