How do I fix error code F dH on a LG refrigerators?

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 Refrigerators

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.

This Error Applies To

LG LF31S6360 Series Refrigerators

Service manual exact match: LF31S6360SService manual exact match: LF31S6360BService manual exact match: LF31S6360WService manual exact match: LF31S6360D