mypros+
Error code reference

LG Refrigerator Error Code E 27

Damper heater error

LG codesLG refrigerator codes

Damper heater error - damper heater sensed as open (RSG5B* model display).

First step from the service manual

Disconnect MAIN PCB CN73 and read resistance between Black and Brown wire terminals; 0 Ohm = heater short, infinite Ohm = wire cut or slipped-out terminal.

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

MyPros+ Max

Get the full diagnostic procedure for E 27.

  • Step-by-step tests with expected resistance, voltage, and continuity values
  • Wiring diagram references and connector pinouts from the OEM service manual
  • Verified part numbers when replacement is required
Get the full procedure

$29/month · Cancel anytime · Or $9.95 3-day pass

What E 27 means on a LG refrigerator

The E 27 error code on LG RSG5B-series refrigerators indicates a damper heater fault, specifically that the control system has detected the damper heater circuit in an open condition. The damper heater is a small resistance heating element located at the air damper assembly, used to prevent ice buildup that would obstruct airflow between the freezer and fresh food compartments. When the main PCB loses continuity through this heater circuit, it logs E 27 and may restrict normal cooling operations to protect the system.

The primary diagnostic entry point is the MAIN PCB connector CN73. Disconnecting this connector and measuring resistance between the Black and Brown wire terminals reveals the fault type immediately. A reading of 0 ohms indicates a shorted heater element or wiring, while an infinite resistance reading points to an open circuit caused by a broken heater element, a severed wire, or a terminal that has pulled back out of the connector housing. These two failure modes require different repair approaches, making this initial resistance check critical before ordering any parts.

Common root causes include physical heater element failure due to age or thermal cycling stress, wiring harness damage from repeated freezing and thawing cycles near the damper assembly, and connector terminal issues at CN73. Because the damper area is exposed to moisture and temperature extremes, wire insulation can become brittle and crack over time, and crimp terminals can corrode or back out of their connector housings. Identifying which condition is present through resistance measurement prevents unnecessary parts replacement.

Source: manufacturer service documentation.

Common causes of E 27

  1. 01

    Open heater element

    Part replacement

    The damper heater element itself has failed internally, breaking the circuit and causing infinite resistance when tested at CN73. This is the most frequent cause and requires replacing the heater assembly.

  2. 02

    Pulled-out or backed-out terminal at CN73

    Wiring / connection

    The Black or Brown wire terminal has slipped out of the CN73 connector housing, breaking continuity without any damage to the wire or heater. Inspect the connector carefully and reseat or re-pin the terminal before assuming the heater itself is faulty.

  3. 03

    Broken or cut wire in the harness

    Part replacement

    Repeated exposure to freezing temperatures and mechanical stress near the damper assembly can cause the wiring harness to crack or break, resulting in an open circuit. Visually trace the Black and Brown wires from CN73 to the heater for any visible damage.

  4. 04

    Shorted heater element or wiring

    Part replacement

    A resistance reading of 0 ohms at CN73 indicates a short in the heater element or associated wiring rather than an open circuit. This is less common but can occur due to insulation breakdown and requires heater or harness replacement.

  5. 05

    Faulty MAIN PCB

    Part replacement

    If the wiring and heater element both test within normal parameters, the CN73 circuit on the main PCB itself may be defective and misreading the heater circuit. The PCB should only be considered after all wiring and component checks are complete.

See the test procedure for each cause

Frequently asked questions about E 27

What does E 27 mean on a LG refrigerator?
E 27 on an LG RSG5B-series refrigerator indicates a damper heater error, specifically that the control board has detected the damper heater circuit as open. The damper heater prevents ice from blocking the air vent between compartments. The fault can be caused by a failed heater element, broken wiring, or a loose terminal at connector CN73 on the main PCB.
How do I fix the E 27 error on my LG refrigerator?
Start by disconnecting connector CN73 on the main PCB and measuring resistance between the Black and Brown wire terminals with a multimeter. A reading of infinite resistance points to an open circuit from a failed heater or broken wire, while 0 ohms indicates a short. Based on the reading, inspect the connector terminals for backing out, trace the wiring harness for damage, and replace the damper heater assembly or repair the wiring as needed.
Is it safe to keep using my refrigerator while E 27 is displayed?
Continued use is not recommended without addressing the fault. The damper heater prevents ice from blocking the air vent, and without it functioning correctly, airflow between compartments can become restricted. This can lead to uneven temperatures, food spoilage in the fresh food section, and potential ice buildup that worsens over time.
Will resetting my LG refrigerator clear the E 27 error?
A power reset may temporarily clear the error code display, but it will not resolve the underlying fault. If the heater circuit remains open or shorted, the E 27 code will return once the control board runs its diagnostic cycle again. A proper repair of the heater, wiring, or connector is required for the code to clear permanently.
How much does it cost to repair an E 27 error on an LG refrigerator?
Repair costs depend on the root cause. If only a terminal needs reseating, the fix may cost little to nothing beyond a service call fee, which typically ranges from $75 to $150. Replacing the damper heater assembly generally costs between $40 and $120 for the part, plus labor. A wiring harness repair or main PCB replacement would increase the total cost, potentially ranging from $200 to $400 or more depending on parts and local labor rates.

Related LG refrigerator codes

All LG refrigerator codes
View all 485 LG refrigerator codes

78,000+ service manuals · 160,000+ error codes · 55+ brands

Get Started

$29/month · Cancel anytime · Or $9.95 3-day pass