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Error code reference

Jenn-Air Refrigerator Error Code F3E5

Evaporator Defrost Thermistor is not working correctly

Jenn-Air codesJenn-Air refrigerator codes

Evaporator Defrost Thermistor is not working correctly — open or shorted.

First step from the service manual

Run Service Test 04; check resistance reading at HV Board P20-11 to P20-12.

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

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What F3E5 means on a Jenn-Air refrigerator

The F3E5 error code on a Jenn-Air refrigerator indicates that the evaporator defrost thermistor is not functioning correctly. This thermistor is a temperature-sensing resistor mounted near the evaporator coil in the freezer compartment. Its primary role is to monitor the evaporator temperature during the defrost cycle, signaling the control board when the coil has reached an appropriate defrost termination temperature. When the board detects a resistance reading that falls outside the expected range, indicating either an open circuit or a short circuit in the thermistor, it logs the F3E5 fault.

To begin diagnosing this fault, a technician should run Service Test 04 and measure the resistance at the High Voltage (HV) Board connector P20, specifically between pins 11 and 12. A reading that is extremely high or reads as infinite suggests an open thermistor, while a reading near zero ohms points to a shorted thermistor. Either condition prevents the control system from accurately tracking evaporator temperature during defrost, which can lead to frost accumulation on the evaporator coil, restricted airflow, and inadequate cooling throughout the refrigerator.

Common causes include a failed thermistor due to age or physical damage, compromised wiring in the harness between the thermistor and the HV board connector, or a corroded or disconnected connector at P20-11 to P20-12. In some cases, moisture intrusion into the connector can cause intermittent faults that are difficult to reproduce. Addressing this code promptly is important because an uncorrected defrost system fault can allow ice buildup on the evaporator coil, ultimately leading to a no-cooling condition.

Source: manufacturer service documentation.

Common causes of F3E5

  1. 01

    Failed Evaporator Defrost Thermistor

    Part replacement

    The thermistor itself has failed internally, resulting in an open or shorted resistance reading at connector P20-11 to P20-12. This is the most frequent cause and is confirmed when the resistance reading is either infinite or near zero ohms during Service Test 04.

  2. 02

    Damaged or Broken Wiring Harness

    Part replacement

    The wiring between the defrost thermistor and the HV board connector can become brittle, pinched, or broken, especially in freezer environments where repeated temperature cycling stresses the insulation. Visually inspect the harness for cuts, kinks, or breaks and check for continuity along each wire.

  3. 03

    Corroded or Loose Connector at P20-11 to P20-12

    Wiring / connection

    Moisture inside the freezer compartment can cause oxidation or corrosion at the HV board connector pins P20-11 and P20-12, leading to high resistance or an open circuit. Inspect the connector for discoloration, corrosion, or pins that are not fully seated.

  4. 04

    Moisture Intrusion at Connector

    Wiring / connection

    Water or ice formation around the thermistor connector can cause intermittent faults that appear and clear on their own. This is more likely if the defrost system has already been compromised or if a previous repair left a connector exposed.

  5. 05

    Faulty High Voltage Board

    Part replacement

    If the thermistor and all associated wiring check out correctly, the HV board itself may be misreading the signal at pins P20-11 to P20-12. This is a less common cause and should only be considered after the thermistor and harness have been ruled out.

See the test procedure for each cause

Frequently asked questions about F3E5

What does F3E5 mean on a Jenn-Air refrigerator?
F3E5 indicates that the evaporator defrost thermistor is not operating correctly, either showing an open circuit or a short circuit. This thermistor monitors evaporator coil temperature during the defrost cycle and reports that data to the control board. When the board cannot get a valid reading from the thermistor, it stores the F3E5 fault code. The issue can stem from a failed thermistor, damaged wiring, or a faulty connector at the HV board.
Can I fix the F3E5 error code myself?
A knowledgeable DIYer can start by inspecting the wiring harness and connector at HV board pins P20-11 to P20-12 for obvious damage, corrosion, or loose connections. If the connector looks clean and secure, testing the thermistor resistance with a multimeter during Service Test 04 will confirm whether the sensor has failed. Replacing the defrost thermistor is a moderately involved repair that requires accessing the evaporator coil behind the freezer back panel. If the HV board is suspected, professional service is recommended.
Is it safe to keep using my refrigerator while the F3E5 code is active?
Short term use is generally possible, but running the refrigerator with a non-functional defrost thermistor carries real risks. Without accurate evaporator temperature data, the defrost cycle may not terminate properly, allowing frost to build up on the evaporator coil. Over time, heavy frost buildup will block airflow and cause the refrigerator to lose cooling ability, potentially spoiling food. It is best to address the fault as soon as possible.
How much does it cost to repair the F3E5 error on a Jenn-Air refrigerator?
If only the defrost thermistor needs replacement, parts typically range from around 15 to 50 dollars, and a repair technician may charge between 100 and 200 dollars for labor depending on your location. If the wiring harness is damaged, expect additional parts and labor costs. A faulty HV board is the most expensive scenario, with board costs ranging from 150 to 400 dollars or more plus labor.
Will resetting the refrigerator clear the F3E5 error code?
A power reset may temporarily clear the code from the display, but it will return as soon as the control board runs a diagnostic cycle and detects the same fault condition at the thermistor circuit. Resetting does not address the underlying hardware problem. The code will continue to appear until the defective thermistor, wiring, or connector is repaired or replaced.

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