How do I fix error code F dH on my LG LF31S6360S?

1. undefined: Step 1: Inspect door gasket for damage or gaps. If damaged, replace door gasket before continuing. 2. undefined: Step 2: Measure defrost heater resistance at CON9 5th Pin ~ 13th Pin (Test Mode 1). Expected: 42~50 ohms. If not 42~50 ohms, check Fuse-M continuity (should be 0~0.1 ohms). Replace Fuse-M if open. 3. undefined: Step 3: Check Fuse-M — measure between its two pins; should read 0~0.1 ohm. If infinite (open), replace Fuse-M. The full sheath heater spec is 62~70 ohms at test point (1)~(2). 4. undefined: Step 4: Measure defrost sensor resistance at CON8 26th Pin ~ 25th Pin. Cross-reference to temperature table (e.g., 32°F=30kΩ, 41°F=24kΩ). If sensor reads open (OL) or 22kΩ when not at that temperature, replace sensor. 5. undefined: Step 5: Enter Test Mode 3 (push test button 3 times; '33 33' displayed). Measure heater voltage at CON9 5th Pin ~ 13th Pin. Should be 112~116V AC. If voltage is absent, check PCB relay output. 6. undefined: Step 6: Enter Test Mode 1 (push button 1 time). Measure heater voltage at CON9 5th Pin ~ 13th Pin. Should be 0V in this mode. If voltage is present in Test Mode 1, replace Main PCB. 7. undefined: Step 7: If voltage in Test Mode 3 is correct and heater is within spec but defrost still fails, explain to customer and check drain tube for blockage.

LG LF31S6360SRefrigerator

Error Code F dH

Defrosting failure — defrost sensor did not reach 40°F (5°C) within 80 minutes after defrost start

Moderate

Address soon - your appliance may not work properly

Also displayed as: F dH

What This Means

Disconnection of thermal fuse (Fuse-M); Defective or open defrost heater; Defective heater relay on PCB; Drain tube blockage; Damaged door gasket causing excessive frost

How to Fix

1
Step 1: Inspect door gasket for damage or gaps. If damaged, replace door gasket before continuing.
2
Step 2: Measure defrost heater resistance at CON9 5th Pin ~ 13th Pin (Test Mode 1). Expected: 42~50 ohms. If not 42~50 ohms, check Fuse-M continuity (should be 0~0.1 ohms). Replace Fuse-M if open.
3
Step 3: Check Fuse-M — measure between its two pins; should read 0~0.1 ohm. If infinite (open), replace Fuse-M. The full sheath heater spec is 62~70 ohms at test point (1)~(2).
4
Step 4: Measure defrost sensor resistance at CON8 26th Pin ~ 25th Pin. Cross-reference to temperature table (e.g., 32°F=30kΩ, 41°F=24kΩ). If sensor reads open (OL) or 22kΩ when not at that temperature, replace sensor.
5
Step 5: Enter Test Mode 3 (push test button 3 times; '33 33' displayed). Measure heater voltage at CON9 5th Pin ~ 13th Pin. Should be 112~116V AC. If voltage is absent, check PCB relay output.
6
Step 6: Enter Test Mode 1 (push button 1 time). Measure heater voltage at CON9 5th Pin ~ 13th Pin. Should be 0V in this mode. If voltage is present in Test Mode 1, replace Main PCB.
7
Step 7: If voltage in Test Mode 3 is correct and heater is within spec but defrost still fails, explain to customer and check drain tube for blockage.