Ronald M Parlin , NJ January 01, 2017 Appliance: Model LMX21981ST/04 Lg er dh code First I changed out the defrost sensor. I knew the defrost heater was working. This did not fix the problem, but was less expensive than the power control board, so I tried it first. Took about 40 minutes to change. Next I changed out the power control board. This fixed the problem. Took less then 10 minutes to change. Read More... 1 People found this story helpful Do-It-Yourself Rating: Repair Time Estimate: 30-60 minutes Tools: Screwdrivers