How to Test and Replace an LG Washer Heater with Thermistor

Is your LG washer not heating properly or leaving clothes damp after a cycle? If so, the heater assembly and thermistor might be to blame. These parts regulate water temperature, and when they fail, your washer can struggle to clean effectively. We’ll walk you through how to test and replace these components, saving you time and money before calling in the pros!

If you need any replacement parts for your LG washer, 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.

What you need

• Towel
• Pair of adjustable pliers
• Flashlight
• Multimeter
• 10 mm socket wrench

Safety tips

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 you attempt any maintenance or replacement work. This keeps you safe by eliminating any risk of electric shock. 
• If the appliance has recently been used, give it plenty of time to cool down before working on it. 
• Take your time while working to prevent accidents and personal injuries. Rushing is the enemy of precision.
• Work in a well-lit area so you can see and access appliance parts.
• Keep your workspace free of clutter and other obstacles. Keep children and pets away from the work area.
• Never work on internal parts with wet hands. Make sure the work area is completely dry.
• Check the user manual to see if there are specific installation or safety instructions related to your appliance or replacement part. 
• Be gentle when handling or removing parts. Excessive force might damage the appliance or cause personal injury.
• Wear insulated work gloves to protect your hands from sharp metal parts and debris.
• 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.
• Always take photos or make a note of wiring terminals or other connections before disconnecting them to make reassembly easier.
• Don’t test live voltage with a multimeter if you’re unfamiliar with how to prevent short-circuiting.
• Consider wearing safety glasses and/or a dust mask when working with chemicals, dust or a large amount of debris to prevent irritation or injury.
• Turn off the water supply at the outlet before beginning repairs. Keep towels ready to catch any residual water in the system when removing parts.

How to test and replace the LG washer’s heater assembly and thermistor

Follow these steps to safely test, remove, and replace the heater assembly and thermistor in your LG washer.

Step 1. Test the heater assembly and thermistor

NOTE: Generally, for every 1 degree in temperature difference, 2 Ohms could be added or subtracted. If the temperature in your home is cooler, resistance would be subtracted.

1. Turn off the power by unplugging the washer.
2. Turn off the water supply to the washer.
3. Place a towel under the washer to catch any water drips.
4. Use pliers to loosen and remove the water inlet hoses from the back of the washer.
5. Tilt the washer onto its left side when facing the front.
6. Place a solid support under the washer to keep it stable.
7. Locate the heater assembly at the bottom front of the outer tub.

1. Set the multimeter to resistance mode (Ω – horseshoe symbol).
2. Use a flashlight for better visibility if needed.
3. Disconnect the white plug from the thermistor.
4. Place the multimeter probes on the thermistor terminals.
5. Check for a resistance reading of about 39.5 KΩ at room temperature (77°F).
6. If the reading is significantly different, replace the thermistor.
7. Remove both wire connectors from the heater terminals.
8. Place the multimeter probes on the heater terminals.
9. Check for a resistance reading between 12 – 18 Ω.
10. If the reading is 0 Ω (short circuit) or infinite (open circuit), the heater is faulty.
11. Switch the multimeter to continuity mode (Wi-Fi-like symbol).
12. Place one probe on a heater terminal and the other on the nut in the middle of the heater.
13. If continuity is detected (beeping sound), the heater is grounded and must be replaced.

Step 2. Remove the heater assembly and thermistor

1. Unplug the washer and confirm it is stable on its left side.
2. Remove the thermistor plug from the assembly.
3. Disconnect both wire connectors from the heater terminals.
4. Use a 10mm socket wrench to remove the central nut on the heater bracket.
5. Slide off the ground wire loop from the post.
6. Use the 10mm socket wrench to loosen the second nut without fully removing it.
7. Hold a towel under the heater assembly to catch any residual water.
8. Pull out the heater assembly from the opening.

Step 3. Install the new heater assembly and thermistor

1. Clean the surface around the heater assembly opening.
2. Insert the new heater assembly with the terminals facing downward.
3. Push the heater assembly into place.
4. Use the 10mm socket wrench to tighten the central nut.
5. Slide the ground wire loop onto the post.
6. Install and tighten the second nut with the 10mm socket wrench.
7. Reconnect the two wire connectors to the heater terminals.
8. Reconnect the thermistor plug.

Step 4. Reset and test the washer

1. Return the washer to an upright position.
2. Reconnect the water inlet hoses by threading them manually onto the inlets.
3. Use pliers to tighten the water inlet hoses securely.
4. Turn on the water supply.
5. Plug the washer back into the power outlet.
6. Run a test cycle to check for leaks and proper heating operation.

We’re here to help

Thanks for following along! We hope this guide made testing and replacing the heater assembly and thermistor in your LG washer a breeze. If you still need parts, bring your model number on over to AppliancePartsPros.com, where you’ll find millions of parts in stock and fast shipping—most arrive in only two days! If you have questions, you can reach us at 1 (877) 477-7278 or chat with us online. Make sure to swing by our DIY blog and YouTube channel for more repair tips. And don’t miss out—follow us on Facebook, X and Instagram to see our latest and greatest!