How to replace the defrost control board 4388931 on a Whirlpool refrigerator

Does your Whirlpool refrigerator have a mind of its own, leaving your food freezing or thawing unexpectedly? The culprit could be a faulty defrost control board, but no worries—we’ve got you covered! With our step-by-step guide and helpful how-to video just below, you can swap out the faulty part yourself and restore your refrigerator’s performance in no time.

Looking for the right part? Enter your appliance model number below to find the exact match and get your appliance running like new again!

On a Whirlpool refrigerator, the defrost control board (part number 4388931) is responsible for regulating the defrost cycle of the refrigerator, allowing your refrigerator to maintain the correct temperature. Common signs that indicate the need for replacement include the refrigerator not running at all, a buildup of frost in the freezer, or inconsistent cooling. Fortunately, with a few basic tools and some patience, you can tackle this repair yourself and get your refrigerator back in working order. So, let’s get started!

If you need any replacement parts for your appliance, 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.

The information in this article may not apply to your specific appliance model. We recommend consulting your manufacturer’s documentation or contact us with any questions.

Watch here: How To: Whirlpool/KitchenAid/Maytag Refrigerator Defrost Control Board 4388931

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.

Tools and materials needed

• Replacement part (make sure it’s compatible with your model before installing)
• 1/4″ nutdriver
• Phillips screwdriver
• Flathead screwdriver

Replacement steps

Step 1: Disassembly and removal

1. Open the fresh food door of the refrigerator.
2. Unplug the refrigerator to ensure safety during the repair.
3. Locate the cover box that protects the thermostat.
4. This cover is secured with a quarter-inch screw. Use a quarter-inch nut driver to remove the screw.
5. Once the screw is removed, gently drop down the cover and pull it slightly forward to disengage it from the locking tabs at the back.
6. Locate the plug at the back of the cover. It may be difficult to see.
7. Use a flathead screwdriver to gently pry the plug out. Insert the screwdriver into the easy tab and carefully pull it down.
8. Identify the three clips holding the sensor bulb in place.
9. Use the flathead screwdriver to pry the sensor bulb out from these clips. Insert the screwdriver behind each clip gently and lift until the bulb is free.
10. Disconnect the plugs from the old control board using the flathead screwdriver. Pry them off gently.
11. There should be two Phillips screws securing the control board. Use a Phillips screwdriver to remove these screws.
12. Once the screws are out, turn the assembly over to access the control board.

Step 2: Installation and reassembly

1. If the new board includes an adapter plug for different configurations, check if it is needed. In this case, you can discard the adapter if it’s not necessary.
2. Begin by plugging in the two plugs to the new control board.
3. Position the control board, ensuring it aligns with the holes.
4. Insert the Phillips screws into their corresponding holes and tighten them securely.
5. Take the assembly back to the refrigerator.
6. Start by placing the sensor bulb back into the clips at the back, ensuring it locks in securely.
7. Align the assembly and ensure that the locking tab is correctly positioned at the back. Press it in until it clicks into place.
8. Place the tube into the cutout and ensure that the rear tabs lock properly into place.
9. Bring the assembly up and secure it with the quarter-inch screw using the quarter-inch nut driver. Tighten it completely.
10. Close the fresh food door of the refrigerator.
11. Plug the refrigerator back into the power source.
12. Check to ensure that the refrigerator is cooling properly.

Additional information

Thanks for reading! We hope this guide helped you replace the defrost control board on your Whirlpool refrigerator.

If you still need some replacement parts, grab your model number and head over to AppliancePartsPros.com. We offer over two million parts and most orders arrive in two business days. If you need some help with finding the right part or placing an order, you can contact our team at 1 (877) 477-7278.

While you’re waiting for your new part to arrive, you can explore our DIY blog and watch thousands of video tutorials on our YouTube channel.

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