Customer Questions and Answers for Defrost Control Board by Whirlpool

Hello Robert. Check and make sure the evaporator fan motor is good in the unit and is running properly. If so, it sounds like the damper assembly is bad and will need to be replaced. You can disassemble the control panel and check to see if the damper door is open. If it is closed or broke, you will need to replace the damper assembly WP61005993.