That's one of the things I have recently fixed on my Vacationer. Here is what I can tell you.........the "Active" light only comes on when the ambient temp drops below about 46 degrees. It is controlled by a thermostat in the wet bay. If your light is on, then you have power. You can confirm this by checking air flow from the heater. If you have air flow, then the switch, thermostat and power are all operating as they should. That only leaves one thing - the element is burnt out.