Dishwasher stops and displays HE; water may be cold or cycle ends prematurely.

Safety first: Turn off power at the breaker. Do not work on the heater circuit with power connected.

• Confirm water temperature: Run a hot water tap at the sink and ensure household hot water is at least 120°F (49°C). Low inlet temperature can contribute to heating issues but will not usually cause HE alone.
• Access heater: Remove the lower front kick panel or pull the dishwasher out to access the underside. Locate the tub heater element (on some LG models integrated into the sump assembly).
• Inspect wiring: Check heater terminals and wiring harness for signs of burning, discoloration, or loose connections. Repair or replace damaged wiring.
• Test heater resistance: With a multimeter set to ohms and power disconnected, measure resistance across the heater terminals. A typical reading is between 10–30 Ω (check service manual for exact spec). An open circuit (OL) indicates a failed heater.
• Check thermistor: If accessible, test the temperature sensor / thermistor for proper resistance change with temperature. Replace if readings are out of spec.

If heater and thermistor test good, the main control board may not be energizing the heater relay and may require replacement by a qualified technician.