Customer Questions and Answers for Defrost Thermostat by Whirlpool

Matt, Wouldn't expect the defrost timer to be at fault, the unit wouldn't cool at all were that the case. There's a remote possibility that the timer contact could be stuck and the heater and compressor could be on at the same time, but that's not all that common. Make sure the interior light goes out when the door is closed and the door closes and seals properly. Remove the light shield, and check that the freezer control damper opens and closes and the assembly is not blocked with ice. Check the shelves, make sure there are no articles hanging over the edge, against the walls blocking the air flow. Check the freezer back wall for a build up of frost or ice on the wall, this would indicate a defrost issue.