Kirk for Model Number WRF990SLAM00 Freezer not getting cold enough, everything checks out in diagnostic mode except defrost heater bimetal is open, the troubleshooting guide says that it if it is open it should be by-passed for the heater to operate. Could this be the reason for the freezer not getting cold and there is ice covering a good portion of the evaporator?
Answer Kirk, the defrost bi-metal being in an open condition will certainly cause a cooling issue as it creates a defrost issue. The defrost bi-metal can be verified for failure from the main control by testing at connection P2 from the pink wire to the brown wire for continuity. If there is not continuity, then the bi-metal has failed. If there is continuity, then it is likely that the main control has failed. The defrost heater can be tested for condition by testing at connection P2 from the brown wire to the white wire at the power supply board on connection P1. The defrost heater should measure 30 ohms of resistance. Read More... Answered by AppliancePartsPros.com | Wednesday, September 25, 2019