Test don’t guess! Check the power to the element and check the resistance of the element, the thermostat and ECO. I have had to replace the ECO twice in 4 years. Much easier than replacing an element.
Atwood 91447 Thermostat Assembly https://www.amazon.com/dp/B00OVBJX3Y/ref=cm_sw_r_cp_api_i_HYj9EbGEAWT4Z