Flipper mullion on a Whirlpool-built French-door refrigerator isn’t heating: How to fix it yourself

If the flipper mullion on your Whirlpool French door fridge isn’t heating, you might notice moisture building up or that it’s not flipping open and closed like it should. The flipper mullion helps prevent condensation by staying slightly warm, so when it stops working, it can affect how well your fridge seals and runs. We’ll walk you through how to troubleshoot the problem and figure out if it’s time to replace the flipper mullion to keep your fridge working properly.

If you find out that you need any replacement parts for your appliance while you’re troubleshooting, you can enter your model number at AppliancePartsPros.com to order them. Most orders arrive in just two business days, and we have thousands of free guides to show you how to install your new parts.

Important: The error code information provided in this article may not apply to your specific appliance model. The disassembly information is based on model KFIS29PBMS02. While we strive to offer helpful advice for DIY appliance repairs, variations in models and configurations can lead to differences in troubleshooting steps, error codes and part replacements. For the most accurate guidance, we strongly recommend consulting the technical sheet for your specific appliance model.

Safety precautions

When working on any appliance, remember to keep safety first. Here are some tips to keep in mind: 

• Always power off and unplug your appliance or switch off the circuit breaker before attempting any maintenance or replacement work. This keeps you safe by preventing any risk of injury from electric shock.
• Wear insulated work gloves to protect your hands from sharp metal parts, pinching hazards and debris.
• Take your time and don’t rush while working to prevent accidents and personal injuries.
• Work in a well-lit area so you can clearly see and access the interior parts.
• Clear your workspace of clutter and other obstacles. Keep children and pets away from the work area.
• Never work on internal parts with bare wet hands. Make sure the work area is completely dry.
• Check your user manual to see if there are specific installation or safety instructions for your part or appliance. 
• Be gentle when handling or removing parts. Excessive force might damage the appliance or cause injury.
• Wear safety glasses when working with chemicals, dust or cleaning large debris to prevent injury. 
• If the appliance has recently been used, give it plenty of time for any heating parts to cool down before working on it. 
• Take pictures or make a note of wiring terminals or other connections before disconnecting to prevent any problems with reassembly.
• When working with wires, avoid touching any exposed wires or terminals. If you need to touch a wire, use a non-conductive tool or wear insulating gloves to prevent electrical shock.

Read more: Fridge Filters: A Master Guide to All You Need to Know

Tools and materials needed

• Multimeter
• Nut driver
• Flathead screwdriver

Important: The specific tools required may vary depending on the model of your appliance and the type of fasteners used on it. Always consult the user manual or refer to any specific instructions provided by the manufacturer for the recommended tools for your appliance model.

Read more: How to move a refrigerator like a pro  

Troubleshooting steps

Step 1: Access the mullion wiring

1. Start by unplugging the refrigerator or turning off the breaker to ensure the power is off.
2. Access the flipper mullion by opening the left-hand door.
3. Make sure the mullion is in the open position, which will expose the mounting screw.
4. Use a 1/4-inch nut driver to remove the screw holding the middle hinge of the mullion to the door.
5. Push the mullion upward to disengage it from the upper and lower mounting tabs. Then push the mullion away from the door.
6. Take off the middle cover that was held in place by the screw, exposing the mullion’s connector.
7. Disconnect the flipper mullion’s connector from the door.

Step 2: Test the mullion

1. Set your multimeter to read resistance (ohms), which is symbolized by an upside-down horseshoe.
2. Place the multimeter leads on the terminals going to the mullion. You should get a reading between 20 and 30 ohms. 
3. If the reading is outside this range, the mullion will need to be replaced.

If the mullion is in range, continue to check for voltage.

Step 3: Voltage test

LIVE VOLTAGE WARNING: For this test, the appliance needs to be plugged in and powered on. Please be very careful to protect yourself from electric shock, which has the potential to cause serious injuries. Don’t ever test live voltage if you’re uncomfortable using a multimeter.

1. Plug the refrigerator back in.
2. Clear any “PO” or “PF” messages on the display by pressing and holding the two buttons furthest to the left on the user interface. A countdown from 3 should appear, and the display should start flashing “01”.
3. Press the 5th button from the left (marked with a plus sign) to advance to test 35, which checks the vertical mullion heater. If the display doesn’t flash “01”, press the options button to switch from “02” to “01”.
4. Set your multimeter to measure DC voltage, then place the leads on the connector coming from the door. You should get a reading between 12-15 volts DC.

If you don’t get the correct voltage, the user interface will need to be replaced. If the voltage is correct and the mullion tested within range, continue testing.

Step 4: Change the heater setting

1. Press the 4th button from the left (with a minus sign) to access test 34. This test allows you to change the mullion heating mode.
2. The default setting “01” runs the heater based on sensor data from the fridge.
3. Change the setting to “02” to make the mullion heat continuously. 

If moisture still forms after this change, the issue could be with the door gaskets or insulation within the doors.

Step 5: Replace the mullion

1. Unplug the refrigerator or turn off the breaker to cut off the power before starting the replacement.
2. Connect the flipper mullion heater harness to the corresponding harness from the door.
3. Position the flipper mullion so the center cover and the upper and lower tabs align correctly.
4. Slide the mullion down, ensuring all mounting points are secured.
5. Use your 1/4-inch nut driver to reinstall the screw that holds the center cover to the door.
6. Reconnect the power cord or turn the breaker back on.
7. Check to ensure the flipper mullion is heating correctly and that the fridge is running smoothly.

Read more: What Temperature Should A Refrigerator Be Set To?  

Additional information

Thank you for reading! We hope this guide helped you get your refrigerator working again.

If you have any other appliance repair needs or projects, don’t hesitate to explore our other troubleshooting guides and videos. 

If you need replacement parts or some extra help with ordering them, grab your model number and head over to AppliancePartsPros.com, where you can chat with a pro, read our DIY blog and more.

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