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Error code reference

LG Refrigerator Error Code 35E

FF Ice Duct Heater Error

LG codesLG refrigerator codes

FF Ice Duct Heater Error — Ice Maker Duct Heater detected as open due to connector slip-out, contact defect, or wire breakage.

First step from the service manual

Measure resistance between CN79 ORG and CN51 BRN on Main PCB; should be 135 ohm ±7%. 0 ohm = heater short, infinity = wire breakage or slip-out.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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What 35E means on a LG refrigerator

The LG 35E error code indicates a fault in the FF (French Door/Freezer) ice duct heater circuit. This heater is responsible for preventing ice buildup inside the ice maker duct, ensuring ice can flow freely without blockages caused by frost accumulation. When the Main PCB detects an open circuit condition in this heater, it triggers the 35E code and flags the component as non-functional. The fault can originate from a physical disconnection, a degraded electrical contact, or a broken wire somewhere along the heater circuit.

Diagnosing the 35E code begins at the Main PCB with a resistance measurement between connector CN79 (orange wire) and CN51 (brown wire). The ice duct heater should read approximately 135 ohms, with an acceptable tolerance of plus or minus 7%. A reading of 0 ohms indicates a short circuit within the heater element itself. An infinite or open resistance reading confirms a wire breakage, a connector that has slipped out of its socket, or a contact defect at one of the terminals. These two readings point the technician in very different directions: a short requires heater replacement, while an open circuit requires a physical inspection of the wiring harness and connectors.

Connector slip-out is among the more common root causes because the ice maker assembly is subject to vibration and repeated thermal cycling, both of which can gradually loosen connector seating over time. Wire breakage can occur at points where the harness flexes or passes through tight routing channels. Contact defects, including corroded or backed-out terminals, can produce an intermittent open that may not always be present when the connector is probed directly. A thorough inspection of the entire harness run between CN79 and CN51 is essential before condemning the heater element itself.

Source: manufacturer service documentation.

Common causes of 35E

  1. 01

    Connector slip-out at CN79 or CN51

    Wiring / connection

    The connector plugging into CN79 (orange) or CN51 (brown) on the Main PCB may have worked loose due to vibration or thermal cycling. Visually inspect both connectors and firmly reseat them, then re-measure resistance.

  2. 02

    Broken wire in the heater harness

    Part replacement

    A wire in the circuit between CN79 and CN51 may have broken internally, often at a flex point or routing clip. This produces an infinite resistance reading and requires tracing the full harness to locate and repair the break.

  3. 03

    Contact defect at a terminal

    Wiring / connection

    A terminal within a connector along the heater circuit may be corroded, bent, or backed out of its housing, causing a high-resistance or open connection. Inspect each terminal for proper seating, corrosion, and secure contact.

  4. 04

    Failed ice duct heater element (open)

    Part replacement

    The heater element itself may have burned out, producing an open circuit. If resistance between CN79 and CN51 measures infinite after confirming all connectors and wiring are intact, the heater element requires replacement.

  5. 05

    Shorted ice duct heater element

    Part replacement

    A resistance reading of 0 ohms between CN79 and CN51 indicates an internal short within the heater element rather than an open circuit. A shorted heater must be replaced and cannot be repaired.

See the test procedure for each cause

Frequently asked questions about 35E

What does 35E mean on a LG refrigerator?
The 35E code on an LG refrigerator indicates that the Main PCB has detected an open circuit in the FF ice maker duct heater. This heater prevents frost from blocking the ice maker chute. The fault is typically caused by a connector that has slipped out, a broken wire in the harness, a contact defect at a terminal, or a failed heater element. A resistance measurement between connector CN79 and CN51 on the Main PCB is the first step to identifying the exact cause.
Can I fix the 35E error myself without calling a technician?
A DIYer with basic electrical knowledge and a multimeter can perform the initial diagnosis by checking resistance between CN79 (orange) and CN51 (brown) on the Main PCB. If the cause is simply a loose connector, reseating it may resolve the error without any parts. However, if a wire needs repair or a heater element needs replacement, comfort with appliance wiring and disassembly is required. If you are unsure, consulting a qualified technician is the safer option.
Is it safe to keep using my LG refrigerator with a 35E error?
A 35E error means the ice duct heater is not functioning, which can allow frost to accumulate in the ice maker chute and eventually stop ice production. The refrigerator's cooling function is generally not immediately compromised, but continued operation without repair can worsen the ice maker blockage over time. It is best to diagnose and address the fault promptly rather than ignore it.
Will resetting my LG refrigerator clear the 35E error code?
A power reset may temporarily clear the displayed 35E code, but the error will return if the underlying fault in the ice duct heater circuit has not been corrected. The Main PCB will continue to detect the open circuit on each diagnostic cycle and re-trigger the fault. A lasting repair requires finding and fixing the root cause, whether that is a loose connector, damaged wiring, or a failed heater element.
How much does it cost to repair a 35E error on an LG refrigerator?
Repair costs vary depending on the root cause. If only a connector needs reseating, there may be no parts cost at all, though a service call fee typically ranges from around 75 to 150 dollars. If the heater element itself needs replacement, parts and labor combined can range from approximately 150 to 350 dollars or more depending on your location and the service provider. Diagnosing the fault first with a multimeter can help avoid unnecessary part replacement.

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