LG Refrigerator Defrost Error Repair in Port St. Lucie

Quick symptom overview

LG French door, 4-door Flex, and side-by-side refrigerators display Er dH (Defrost Heater Error on fresh food or freezer evaporator) or Er dF (Freezer Defrost Error) when the electronic main PCB control board (EBR73093601, EBR82230401, EBR75812801) senses that evaporator temperature has failed to reach 46°F (8°C) within 80 minutes of activating Calrod Sheath Defrost Heater 5300JB1100R (supersessions AEC73820201, 5300JB1100C, ME31861001).

The automatic defrost system consists of: Main PCB → 120 VAC defrost relay → cabinet wire harness → defrost bimetal safety thermostat / thermal fuse assembly 6615JB2005C (cuts off at 158°F / 70°C) → 120 VAC 280W glass/sheath defrost heater 5300JB1100R → NTC evaporator thermistor 6322JB1010A. Every 6 to 16 hours of compressor run time, the board enters defrost mode to melt frost off the aluminum evaporator fins. If a burnt heater element (∞ Ω), blown thermal bimetal fuse (∞ Ω), or open board relay breaks the 120V circuit, frost accumulates until airflow is choked off and temperatures rise above 50°F.

Er dH with solid ice wall behind freezer drawers: Burnt sheath defrost heater (∞ Ω) or blown bimetal controller 6615JB2005C. Er dH with water pooling under crisper drawers: Clogged defrost drain trough tube 5214JA3003A or frozen drain strap extension. Related LG repair guides: LG washer OE & LE hall sensor guide, LG electric dryer dE / dE1 door switch guide, and LG refrigerator Er IF / Er FF fan motor guide. Local service page: LG appliance repair.

Safety: Unplug the refrigerator power cord before removing interior back duct panels or handling defrost heater terminals. Evaporator fins are sharp—wear cut-resistant gloves.

Step-by-step diagnostic hierarchy

1. Perform Forced Defrost Mode test (Power ON — live test) — Press the Test Button on main PCB (behind rear cabinet access cover) 2 times:

   • The compressor and evaporator fans will shut off, and the display will show 22 22 or d H:
     • Listen at lower rear freezer panel for crackling heat sounds or feel for warmth at bottom of evaporator wall.
     • Heater warms up within 3 minutes: Intermittent harness connection or false sensor error.
     • Heater stays ice cold: Proceed to component resistance checks.

2. Measure sheath defrost heater resistance (Power OFF — meter check) — Unplug refrigerator, remove freezer drawers, and unbolt interior rear plastic evaporator wall (4 Phillips screws):

   • Unclip 2-pin harness connector from sheath heater 5300JB1100R at bottom of evaporator coil.
   • Set multimeter to 200 Ω scale:
     • Measure across the 2 spade terminals of heater 5300JB1100R:
     • Expected normal reading: 25.0 Ω to 35.0 Ω at room temperature (typically 30 Ω).
   • Result: ∞ Ω (Open circuit): Heating element calrod is burned out → replace Defrost Heater Assembly 5300JB1100R / AEC73820201.

3. Test defrost bimetal safety thermostat / fuse 6615JB2005C (Power OFF — meter check) — Locate yellow/white 4-pin harness assembly 6615JB2005C clipped to top return bend of evaporator coil:

   • Disconnect harness plug. Set meter to 200 Ω range:
     • Measure across the bimetal switch wires:
     • Cold / Coated in Frost (< 14°F / -10°C): Expected < 0.5 Ω (Closed circuit).
     • Warm / Room Temp (> 40°F / 4°C): Expected ∞ Ω (Open circuit).
     • Measure across thermal inline fuse wires: expected < 0.5 Ω at all temperatures.
   • Result: ∞ Ω when frost-cold: Bimetal contact or internal 158°F thermal safety fuse is blown → replace Defrost Controller Assembly 6615JB2005C.

4. Measure NTC evaporator thermistor 6322JB1010A resistance (Power OFF — sensor check) — Locate thermistor probe 6322JB1010A attached to center evaporator fin:

   • Set meter to 20k Ω (20,000 Ω) scale:
     • 32°F (Ice water / 0°C): Expected 10.0 kΩ to 11.5 kΩ (10.8 kΩ nominal).
     • 77°F (Room temp / 25°C): Expected 3.0 kΩ to 3.5 kΩ (3.3 kΩ nominal).
   • Result: ∞ Ω (Open) or < 200 Ω (Shorted): Replace Evaporator Thermistor 6322JB1010A.

5. Test 120 VAC defrost power output from Main PCB (Power ON — live check) — Re-seat heater/bimetal plugs, plug in refrigerator, enter forced defrost mode (Test Button x2), and measure voltage across main PCB header CON3 Pin 1 to CON3 Pin 3:

   • Set multimeter to 200 VAC range:
     • Expected: 110 VAC to 125 VAC.
   • Result: 0 VAC output from board: Defrost relay contacts burned out → replace Main PCB Assembly (EBR73093601 / EBR82230401).

Multimeter and safety checks

Disconnect 120V AC power cord before taking resistance measurements or unplugging heater harness connectors.

Component / Test	Setup & Meter Range	Expected Normal Value	Fault / Failure Mode
Defrost Heater 5300JB1100R	Across 2 heater terminals, 200 Ω	25.0 Ω–35.0 Ω	∞ Ω (burnt sheath element; logs Er dH)
Defrost Bimetal (Frost Cold)	Across bimetal lead pins, 200 Ω	< 0.5 Ω	∞ Ω when frozen (blown bimetal safety switch)
Thermal Safety Fuse	Across inline fuse pins, 200 Ω	< 0.5 Ω	∞ Ω (blown 158°F thermal cut-out fuse)
Evaporator Thermistor (32°F)	Across sensor pins, 20k Ω	10.0 kΩ–11.5 kΩ	∞ Ω (failed NTC sensor; causes no defrost)

Root cause vs repair breakdown

Observable Symptom	Root Cause / Faulty Part	Corrective Repair Action
Er dH code, heater resistance reads ∞ Ω	Burnt internal calrod heating wire	Replace Defrost Sheath Heater 5300JB1100R / AEC73820201
Er dH code, bimetal reads ∞ Ω when iced	Blown 158°F thermal fuse or bimetal	Replace Defrost Controller Assembly 6615JB2005C
Er dH code, 0 VAC output from main PCB	Open defrost relay on main control PCB	Replace Main PCB Assembly EBR73093601 / EBR82230401
Standing ice sheet in bottom of freezer	Clogged rubber drain duckbill valve	Steam drain trough; clean/replace drain valve 5214JA3003A

FAQ

What does Er dH mean on an LG French door or side-by-side refrigerator?

Er dH (Defrost Heater Error) indicates a Defrost System Failure. The main PCB control board (EBR73093601 / EBR82230401) detects that evaporator thermistor 6322JB1010A temperature did not rise above 46°F (8°C) within 80 minutes of energizing defrost heater assembly 5300JB1100R.

How do I test LG defrost heater assembly 5300JB1100R with a multimeter?

Unplug the refrigerator, remove the rear freezer duct wall, and unclip the defrost harness connector. Set multimeter to 200 Ω scale: measure resistance across the 2 spade terminals of sheath heater 5300JB1100R: expected normal resistance is 25 Ω to 35 Ω (30 Ω typical). An ∞ Ω reading indicates a burnt, open heater element.

How do I test LG defrost bimetal thermostat 6615JB2005C?

Unplug power. Locate bimetal fuse harness 6615JB2005C clipped to the top loop of the evaporator coil. Set multimeter to 200 Ω scale: when frost-cold (< 14°F / -10°C), expected reading is < 0.5 Ω (closed circuit). At room temp (> 40°F), bimetal opens (∞ Ω). If bimetal reads ∞ Ω when coated in ice, the thermal fuse is blown.

Should I replace defrost heater 5300JB1100R, bimetal 6615JB2005C, or main PCB?

If sheath heater resistance reads open (∞ Ω), replace Defrost Heater Assembly 5300JB1100R. If bimetal fuse reads ∞ Ω when cold, replace Defrost Controller Assembly 6615JB2005C. If heater and bimetal test normal (< 35 Ω and < 0.5 Ω) and 120 VAC is missing at main PCB header CON3 during forced defrost mode, replace Main PCB EBR73093601.

When to schedule professional service

If main PCB control board replacement, sealed system evaporator defrosting, or cabinet wiring harness repair is required, certified LG refrigerator technicians are available. Schedule LG refrigerator repair → or contact our technical department.