I have a 2016 Sundance Optima (no stereo), Serial#100597217 that is not heating past 80 degrees. In the settings and information screen it says the high limit is set to 80 and that seems to me what may be wrong. How can i edit this setting and does that sound like the problem? The heater icon is flashing on the screen and the water temperature is currently 80 but it was dropping one degree every 2 hours last night. Thank you!