Hi, yes the control board needs to be replaced. If you go to www.thetford.com, and select the various model numbers in the Marine section, you'll find pictures to help you identify your model. When you find it, select the 'parts' tab on the right side of your screen. From there you can get the part number for the correct control board. Norcold sells parts through their authorized dealers only. To locate the dealer nearest to you, use the dealer locator tab.