Kenmore Dishwasher Not Heating Water — Heater Designs by OEM Platform

A Kenmore dishwasher that is not heating water will produce poorly cleaned dishes, leave detergent residue, and fail to sanitize. The heating system on your Kenmore dishwasher depends on its manufacturing platform, and this distinction critically affects diagnosis. Whirlpool-platform 665 models use a visible exposed calrod element that you can inspect and test without tools. LG-platform 630 models conceal the heater inside the sump assembly where visual inspection is impossible — requiring electrical testing from the underside of the unit.

Heating System Identification

Whirlpool 665 Platform — Exposed Calrod Element

Open your dishwasher and look at the very bottom of the tub. If you see a horseshoe-shaped metal loop (similar to an oven element) sitting just above the tub floor, you have the Whirlpool exposed element design. This element serves dual duty: heating wash water to the target temperature and providing radiant heat during the Heated Dry phase.

The element connects to the control board through the tub floor via two terminals accessible from underneath (behind the kick panel). Standard resistance: 15-30 ohms between terminals.

LG 630 Platform — Concealed Heater

Open your LG-platform Kenmore dishwasher and look at the tub floor — you will see only the filter basket and sump cover. The heater is hidden beneath the sump housing, integrated into the water circulation path. Water flows past the heater element as it circulates through the system. This design eliminates the risk of items falling onto a hot element but makes inspection impossible without disassembly.

The concealed heater on LG-platform models is paired with a thermistor that provides temperature feedback to the control board.

Kenmore Elite (Bosch Platform) — Flow-Through Heater

Bosch-manufactured Kenmore Elite dishwashers use a flow-through heater integrated into the circulation pump assembly itself. The heater is a tube that water passes through as it circulates. This design heats water extremely quickly (reaching target temperature within minutes) but cannot be replaced independently of the pump assembly on most models.

Diagnosing No-Heat Condition

Step 1: Confirm the Water is Actually Cold

Before investigating components, verify that incoming water is hot:

1. Run the kitchen hot water tap for 60 seconds to purge cold water from the pipes.
2. Start the dishwasher immediately after (while the hot water line is primed).
3. After 5 minutes of the wash cycle, pause the cycle and carefully open the door. Touch the water at the tub bottom — it should be too hot to hold your hand in comfortably.

If the water feels warm (not hot) even after pre-running the tap, the issue is confirmed as a heater component failure rather than a cold water supply problem.

Step 2: Platform-Specific Testing

Whirlpool 665 Platform — Visual and Electrical Test:

1. With the dishwasher empty and powered off, visually inspect the calrod element. Look for:
   • Blisters or bubbles on the element surface (short circuit forming)
   • A visible break in the element (burned through)
   • Discoloration indicating a hot spot
2. Disconnect power at the breaker. Remove the kick panel.
3. Locate the two element terminals protruding from the bottom of the tub.
4. Disconnect the wires from both terminals.
5. Measure resistance across the terminals with a multimeter: 15-30 ohms = good; infinite (OL) = burned out; near zero = shorted.
6. Test each terminal to the tub frame for ground fault: any continuity to ground = dangerous short, replace immediately.

LG 630 Platform — Electrical Test Only:

1. Disconnect power at the breaker.
2. Remove the kick panel and locate the heater wires at the bottom of the sump assembly (usually two heavy-gauge red or brown wires on a dedicated connector).
3. Disconnect the heater connector.
4. Measure resistance across the heater pins: 10-20 ohms = good; infinite = burned out.
5. Test each heater pin to the sump housing for ground fault.
6. Also test the thermistor (separate connector, thinner wires): should read approximately 50k ohms at room temperature.

DIY Difficulty: Moderate (Whirlpool exposed element = straightforward access); Moderate to Difficult (LG concealed heater may require sump disassembly) Parts Cost: $25–$65 for element (Whirlpool); $45–$100 for concealed heater (LG) Professional Repair Cost: $150–$300

Step 3: Testing the Control Board Output

If the heater element tests good but water remains cold, the control board may not be sending power to the element. On Whirlpool-platform 665 models, verify 120V AC at the element connector during the wash phase (requires carefully accessing live wires — professional recommended). On LG-platform models, voltage testing at the heater connector during operation confirms whether the board is commanding the heater.

A board that does not energize the heater despite a good element and good thermistor needs replacement. On Whirlpool-platform models, the relay that controls the heater is a common failure point on the control board.

Component Replacement

Whirlpool 665 — Element Replacement

1. Disconnect power and remove the kick panel.
2. Pull wire connectors off both element terminals.
3. Remove the lock nuts (3/8-inch socket) from both terminals.
4. From inside the tub, push the old element up and out. The rubber grommets may resist — gentle rocking helps.
5. Clean the mounting holes and grommets of mineral scale.
6. Insert the new element from inside the tub, push terminal posts through the floor.
7. From underneath, add new lock nuts and torque to 6 ft-lbs. Over-tightening cracks the ceramic insulators.
8. Reconnect wires and restore power. Run a short cycle to verify heating.

LG 630 — Concealed Heater Replacement

1. Disconnect power and water. Pull the dishwasher out from the cabinet.
2. Lay the unit on its back and remove the base plate.
3. The heater assembly connects to the sump housing — the exact mounting varies by specific model within the 630 series.
4. Disconnect the heater electrical connector and any mounting hardware.
5. On most models, the heater slides out of a sleeve in the sump — pull gently with a twisting motion.
6. Install the new heater with a light coating of thermal grease on the mounting sleeve contact area.
7. Reconnect, reassemble, and test.

Thermistor Failure Mimicking No-Heat

On both platforms, a failed thermistor can cause the same symptom as a failed heater. If the thermistor reports to the control board that water is already at target temperature (when it is actually cold), the board never commands the heater to activate. The heater is functional but never receives power.

Test the thermistor resistance at room temperature:

• Whirlpool 665 platform: thermistor located in the sump area, reads approximately 55k ohms at 72F
• LG 630 platform: thermistor in the sump housing, reads approximately 50k ohms at 72F

A reading significantly lower than expected (under 10k at room temperature) suggests the sensor is telling the board the water is hot when it is not.

Impact of No-Heat on Dishwasher Function

Beyond poor cleaning, a no-heat condition affects other dishwasher functions:

• Longer cycles: The turbidity sensor on Whirlpool models detects food still on dishes and extends the cycle indefinitely trying to achieve clean water
• Detergent residue: Pods and tablets require minimum 120F to dissolve fully
• Sanitize cycle failure: The NSF sanitize cycle requires water reaching 150F — impossible without a functional heater
• Eventual control board fault: On LG-platform models, repeated failure to reach target temperature eventually triggers error code HE or tE

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Kenmore dishwasher not heating? Our technicians test both the heating element and thermistor to identify the exact failure — carrying replacement parts for Whirlpool and LG platform Kenmore units. Schedule a repair →