How to Replace an LG Dishwasher Heating Element: Fix HE Error and Cold Water Cycles

The HE error code on LG dishwashers indicates the heating system failed to raise water temperature to the target within the expected timeframe. LG dishwashers use a concealed heating element mounted beneath the tub floor that heats water during the wash and sanitize cycles. When this element fails, your dishes come out cold and poorly cleaned, and the sanitize cycle will not complete. This guide covers testing the element, accessing it through the bottom of the unit, and installing the replacement.

Unlike older dishwashers with exposed calrod elements inside the tub, LG uses a concealed heater beneath the stainless steel tub floor. This design is safer (no risk of melted plastics touching the element) but makes replacement slightly more involved since you access it from underneath rather than inside the tub.

Before You Start

• Tools needed: Phillips #2 screwdriver, Torx T15 driver, multimeter, adjustable wrench, towels, cardboard (to lie on)
• Parts needed: LG dishwasher heater assembly (model-specific, ~$40-$90)
• Time required: 45-60 minutes
• Difficulty: Advanced
• Safety warning: Disconnect power at the circuit breaker AND unplug at the outlet. The heating element operates at 120V with significant current draw. Verify power is off with a non-contact voltage tester before touching any wiring. Also close the water supply valve.

Diagnosing Heater Failure

Confirm the heater is actually failed before ordering:

1. HE error code displayed: This is the direct indication that the control board detected insufficient temperature rise. However, HE can also be triggered by a failed thermistor (temperature sensor) sending incorrect readings.

2. Cold water at end of hot cycle: Start a Normal or Heavy cycle. After 20 minutes, press cancel and open the door. If the water pooled in the tub bottom is not hot (should be 130-150F), the heater is not working.

3. Sanitize cycle fails to complete: The sanitize option requires water to reach 155F. If the heater cannot reach this temperature, the cycle aborts and the Sanitize indicator will not illuminate at cycle end.

4. Test with multimeter: Access the heater terminals (see Step 3 below) and disconnect the wires. Measure resistance across the two heater terminals. A good LG heating element reads 10-30 ohms. Open circuit (OL) means the element has burned through. Very low resistance (under 5 ohms) suggests a short.

5. Also test the thermistor: While you have access, test the temperature sensor. Disconnect its connector and measure resistance at room temperature — should read 40,000-60,000 ohms (NTC type). If it reads OL or near zero, the sensor is failed, and the HE error may be caused by the sensor, not the heater.

Step-by-Step Instructions

Step 1: Prepare the Work Area

Disconnect power at the breaker and unplug the unit. Close the water supply valve. Open the door and remove both dish racks. Remove the pull-up filter assembly from the tub floor (lift straight up). Use a turkey baster or cup to remove standing water from the sump. Place towels on the floor in front of the dishwasher.

Step 2: Pull the Dishwasher Out from the Counter

Remove the two mounting screws at the top of the door frame (inside the door, screwed into the countertop underside). These hold the dishwasher in place. Disconnect the drain hose under the sink and cap it with a towel. Disconnect the water supply line. Carefully slide the dishwasher forward out of its cabinet space. You need access to the bottom of the unit.

Step 3: Remove the Bottom Access Panel and Insulation

Tip the dishwasher back slightly (lean it against the counter behind, or have a helper hold it at 30 degrees). Alternatively, lay it on its back on a blanket if you have space. Remove the bottom access plate (4-6 Phillips screws). LG dishwashers have a sound insulation pad (part of the LoDecibel system) attached to the bottom — carefully peel this back or remove it to access the tub underside. The heating element terminals protrude through the bottom of the tub with rubber grommets sealing each terminal pass-through.

Step 4: Disconnect the Heater Wiring

Locate the two heater terminal wires. They connect via spade connectors to the terminals protruding from the tub bottom. Pull each spade connector straight off the terminal (use needle-nose pliers if they are tight). Label or photograph which wire goes to which terminal.

Step 5: Remove the Old Heating Element

The heating element is secured by a central mounting nut and bracket from the outside. Loosen and remove this nut (typically 10mm or adjustable wrench). There is a rubber compression gasket that expands when the nut is tightened, creating a watertight seal. With the nut removed, push the element terminals inward (from outside the tub toward the inside). Go to the inside of the tub and pull the element up through the tub floor. The element is a curved metal rod that sits beneath the tub floor in a recessed channel.

Step 6: Install the New Heating Element

Feed the new element down through the tub floor opening(s) from inside the tub. Position it in the recessed channel beneath the tub floor. From underneath, slide the rubber compression gasket over the terminals, then thread the mounting nut. Tighten the nut to compress the gasket — this creates the watertight seal. Do not overtighten — you only need the gasket to bulge slightly against the tub surface. Reconnect the spade wire connectors to the terminals.

Step 7: Reassemble and Reinstall

Replace the insulation pad and bottom access plate. Slide the dishwasher back into the cabinet space. Reconnect the water supply line (hand-tight plus quarter-turn), the drain hose (push onto barb and secure with clamp), and reinstall the mounting screws into the countertop. Restore the water supply valve and check for leaks at the supply connection.

Step 8: Test the New Heater

Restore power at the breaker. Reinstall the filter assembly (push down into place). Run a Normal cycle with hot wash setting. After 15-20 minutes, open the door and check water temperature — it should be noticeably hot (130F+). Run the full cycle to completion and verify no HE error appears. If your model has a Sanitize option, run a sanitize cycle and confirm the Sanitize indicator illuminates at cycle end (confirming water reached 155F).

Troubleshooting After Replacement

• HE error returns with new element: The thermistor (temperature sensor) may be sending incorrect readings to the control board. Test the sensor resistance — it should change predictably with temperature (lower resistance at higher temps for NTC type). Replace if readings are erratic.
• Element works but dishes still have spots: This is likely a rinse aid issue, not a heater issue. Ensure the rinse aid reservoir is full and the dispenser dial is set to 3-4.
• Water leaks from element area after installation: The compression gasket is not properly sealed. Remove the bottom panel, tighten the mounting nut slightly more (quarter-turn increments until leak stops).
• Thermal fuse blows after new element installation: If the new element has a lower resistance than spec (drawing more current), it can blow the thermal fuse. Verify your replacement part matches the OEM resistance specification.

When to Call a Professional

• You need to pull the dishwasher out and do not feel comfortable disconnecting plumbing
• The tub bottom is corroded around the element mounting holes — seal integrity may be compromised
• HE error persists after both heater and thermistor replacement — control board issue
• You cannot access the bottom of the dishwasher (built-in custom cabinetry blocking removal)

Cost Comparison: DIY vs Professional

Need Professional Help?

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• Dishwasher repair cost guide

FAQ

Q: What does the HE error code mean on an LG dishwasher? A: HE means the control board detected that water temperature did not reach the expected level within the programmed timeframe. It is triggered by either a failed heating element or a faulty thermistor (temperature sensor). Test both before replacing.

Q: Can I see the heating element inside my LG dishwasher tub? A: No. LG uses a concealed heater beneath the tub floor — you cannot see it from inside. This is different from older dishwashers with exposed calrod elements. Access is from the bottom of the unit by removing the base plate.

Q: How do I test the LG dishwasher heating element with a multimeter? A: Disconnect power. Access the element terminals from the bottom of the unit. Disconnect the wires. Set multimeter to ohms and measure across the two terminals. Normal reading: 10-30 ohms. OL (infinity) = burned-out element. Near zero = shorted element. Both mean replacement needed.

Q: Does the LG dishwasher heat its own water or use hot from the tap? A: Both. LG dishwashers connect to your hot water supply line and further heat the water with the built-in element to reach optimal wash temperature (130-150F) and sanitize temperature (155F). Running hot water at the sink before starting ensures the dishwasher receives hot water immediately.

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