LG refrigerator F dH error code

Refrigerator & Freezer Repair
1

My 33 month old LG refrigerator Model LFXS29766S has been displaying F dh error code for the past few days. I have cleared the code after power cycled. Approx. one day later the code is back. I have done this three times now. When the code is displayed refrigerator and freezer are working however the touch controls don’t respond and the water and ice functions are disabled.

An internet search on this code give me this information.
LG Error Code F dH = Error is Sensor didn’t get over 40F in Defrost = Repair or Check Faulty Fuse, Heater, or Control Board = Part or parts that need to be checked or replaced are… Controller Assembly, Defrost Heater, or Relay on Control Board

I’m looking for help on how to proceed next. I don’t have any tech information to troubleshoot the possible cause. I have a multi meter and have repaired many various electronic stuff. Many moons ago I was a repair tech on copy machines, laser printers, and computers. I can read voltage and signals on connector pins and disassemble the whole refrigerator if needed.

If anyone has suggestions, input, or schematics to help me nail down the correct part I would greatly appreciate it. Thanks

2

Well after lots of searching for my specific issue all I came across was components of the heater circuit. I found a schematic on the back of the refrigerator and used it to trace the heater, thermistor, and thermal fuse. I disassembled the bottom freezer section and exposed the evaporator which was frozen solid. I used a hair dryer to melt the ice and cleaned everything up. Using my multi meter I tested the heater which beeped and read on the ohm setting. The thermistor value changed when I put heat on it with the hair dryer. I found the thermal fuse to not read on the meter. So I put everything all back together and works perfect although I’m going to have the same problem again until I order the thermistor / thermal fuse harness and do it all over again. I will manually defrost the refrigerator until I get the part in. I also cleaned the condenser coil which was pretty dirty too.

The hardest part of the job was dealing with the arthritis in my knee. This repair was pretty easy. Changing the oil in my truck is harder. Well I’m not sure how much money I just saved but my wife is super happy and now willing to give me a special favor. Oh yeah.