i am purchasing a 2021 rockwood mini lite 2019S. how do i confirm that there are heating pads on the fresh water, grey water and black water tanks. I was told there was but I cannot view them as the undercarriage is covered. There is a indicator light on a panel to the right of the entrance door that says heater. I am not sure if this is the heater switch for those pads. I did not test that light when we checked out the unit. the salesperson states that is the switch.