How do I fix error code F dH on my LG LL31H6530S?

1. undefined: Check door gasket for damage. If gasket is damaged, replace the door gasket. 2. undefined: Check defrost heater resistance at CON9 pins 5–13 (Test Mode 1, 0V expected when heater off). Target resistance 42–50 ohms for the combined circuit. If not in range, check Fuse-M continuity (should read 0 ohms). If Fuse-M is open (infinite), replace Fuse-M. If heater is open, replace heater. 3. undefined: If defrost sensor resistance is not ~22k ohms (at room temp) or is open, replace the defrost sensor/controller assembly. 4. undefined: Enter Test Mode 3 (push test button 3 times). Check voltage at CON9 pins 5–13; expected 112–116V during defrost. If voltage is not present, replace Main PCB. 5. undefined: Enter Test Mode 1 (push test button 1 time). Check voltage at CON9 pins 5–13; expected 0V when not in defrost. If voltage is not 0V, replace Main PCB. 6. undefined: If all checks pass, explain to customer — unit is operating normally.

LG LL31H6530SRefrigerator

Error Code F dH

Defrost heater failure

Moderate

Address soon - your appliance may not work properly

How to Fix

1
Check door gasket for damage. If gasket is damaged, replace the door gasket.
2
Check defrost heater resistance at CON9 pins 5–13 (Test Mode 1, 0V expected when heater off). Target resistance 42–50 ohms for the combined circuit. If not in range, check Fuse-M continuity (should read 0 ohms). If Fuse-M is open (infinite), replace Fuse-M. If heater is open, replace heater.
3
If defrost sensor resistance is not ~22k ohms (at room temp) or is open, replace the defrost sensor/controller assembly.
4
Enter Test Mode 3 (push test button 3 times). Check voltage at CON9 pins 5–13; expected 112–116V during defrost. If voltage is not present, replace Main PCB.
5
Enter Test Mode 1 (push test button 1 time). Check voltage at CON9 pins 5–13; expected 0V when not in defrost. If voltage is not 0V, replace Main PCB.
6
If all checks pass, explain to customer — unit is operating normally.