Dishwasher Not Heating? Here’s What To Check
The machine completes its cycle. The pump runs, the arms spray, the timer counts down. But the dishes come out wet, greasy, or exactly as dirty as they went in — and the door felt cold when you opened it.
Here’s the thing most people get wrong: a dishwasher that won’t heat is usually not a failed heating element. The element is one link in a chain that includes the thermostat, the high-limit thermostat, and the control board relay. Testing the element first and ordering a part is how people spend $75 fixing the wrong component.
For the cost comparison across every dishwasher fault — and the honest repair-or-bin thresholds — see Dishwasher Repair vs Replace: What Each Really Costs.
And there’s a second thing most people miss: the high-limit thermostat — a $10 to $25 part — is the most commonly misdiagnosed component in the heating circuit. It trips when the machine overheats, which often happens because of a scaled element. Replace the element, the new one scales up the same way, and the high-limit trips again.
The single most useful check is free. Before testing any component, confirm the machine is getting hot water from the supply. A cold fill, a closed valve, or a machine connected to cold only produces exactly the same symptom as a failed element — and costs nothing to fix.
For the full heating circuit diagnosis — element, thermostat, high-limit, control board, and the multimeter tests for each — see the guide linked at the bottom, or start with the Dishwasher Repair vs Replace hub for the cost comparison.
Quick Checks Before You Open Anything
Run through these first. They cost nothing, and one of them resolves a real share of “no heat” complaints.
Is the water hot at the tap? Run the hot tap at the sink for 30 seconds. It should be hot. If it isn’t, the problem is upstream of the machine.
Is the machine connected to the hot supply? Check the inlet hose under the sink. Some machines are cold-fill only by design; most aren’t. A machine switched to cold fill will struggle to reach temperature.
Is the inlet valve fully open? A partially closed valve reduces flow and can prevent the machine filling enough to heat properly.
Does the door feel cold mid-cycle? Open the machine during the wash and feel the inside of the door and the water. Cold means no heat at all. Warm but not hot means partial heating.
Do the dishes come out wet but the machine felt hot? That’s a drying fault, not a heating fault — check the rinse aid first.
Is there scale visible on the element? If you can see the element, white crusty deposits mean it’s scaled. A scaled element heats inefficiently and is a common precursor to failure.
Is there a burning smell during the cycle? Stop using the machine and inspect the element and wiring before running another cycle.
If none of those resolve it, work through the faults below in order.
1. Failed Heating Element
Why it stops the machine heating: The element is a resistive coil that heats the water. It corrodes and burns out with age, particularly in hard-water areas where scale builds on the surface and causes localised overheating. When the coil fractures, the circuit is open and no heat is produced.
This is the most common cause of no heat at all, and the most straightforward to test.
Symptoms:
No heat at all on any cycle
Dishes come out cold and wet
The door feels cold when you open it mid-cycle
Visible blistering or cracking on the element
The element may glow briefly then go dark on some models
How to test it:
Disconnect the power at the breaker and shut off the water. Access the element — base-mounted under the sump, side-mounted behind the side panel, or flow-through inline on the circulation pump. Disconnect the wires and test resistance across the two terminals with a multimeter. A good element reads a low resistance — typically 10 to 30 ohms. An infinite reading means it has burned out.
Cost: $25–$75 for the part, $150–$350 installed.
Repair or Bin? Repair on a machine under eight years old. Well under the 50% line.
2. Failed Thermostat
Why it stops the machine heating: The thermostat regulates the water temperature by switching the element on and off. If it fails open — stuck in the off position — the element never receives power and the water stays cold. If it fails closed, the machine overheats and the high-limit thermostat trips.
Symptoms:
No heat at all on any cycle
Heat comes on then cuts out and never returns
The machine overheats (if the thermostat fails closed)
The cycle takes much longer than it used to
How to test it:
Disconnect the power and access the thermostat — usually a small disc or cylinder mounted on the tub or element housing. Disconnect the wires and test continuity at room temperature. A good thermostat reads continuity (closed) at room temperature. No continuity means it has failed open.
Cost: $20–$50 for the part, $100–$200 installed.
Repair or Bin? Repair. Cheap part, and it’s the second most common cause after the element.
3. Blown High-Limit Thermostat
Why it stops the machine heating: The high-limit thermostat is a backup safety cut-out that trips if the machine severely overheats — usually caused by a scaled element or a failed main thermostat. Some reset automatically when cool; others are one-time devices that must be replaced.
This is the most commonly misdiagnosed component in the heating circuit. People replace the element, the new one scales up the same way, and the high-limit trips again — because the underlying cause was never addressed.
Symptoms:
No heat at all
The fault followed a period of poor heating performance
Visible scale on the element
The machine may have overheated previously
Burning smell before the failure
How to test it:
Disconnect the power and locate the high-limit thermostat — usually next to the main thermostat on the element housing. Identify whether it’s a resettable type (some have a small reset button) or a one-time device. Test continuity at room temperature. No continuity means it has tripped. If it’s resettable, press the reset button and test again. If it resets, find out why the machine overheated before assuming the thermostat is the fault.
Cost: $10–$25 for the part, $80–$180 installed.
Repair or Bin? Repair — but fix the underlying cause, or it will trip again.
4. Scaled Element
Why it stops the machine heating: Scale builds on the element surface in hard-water areas. The scale insulates the element, so it can’t transfer heat to the water efficiently. The element overheats locally, which either burns it out directly or trips the high-limit thermostat. A scaled element often produces partial heating rather than total failure — which is why it’s easy to miss.
Symptoms:
Dishes sometimes dry, sometimes don’t
The cycle takes longer than it used to
Performance worse in winter (colder incoming water)
Visible white or chalky deposits on the element
The machine works better after a hot descaling cycle
How to test it:
Access the element and inspect the surface with a torch. Scale appears as a white, chalky, or crusty deposit. Test the element resistance — if it still reads within range, it hasn’t failed but it is scaled.
Cost: $0–$20 in descaler materials. Remove the element and soak in a 50/50 white vinegar and water solution for 30 minutes, then scrub gently.
Repair or Bin? Repair. Free or cheap, and it prevents the high-limit thermostat tripping.
5. Failed Control Board Relay
Why it stops the machine heating: The control board switches power to the element via a relay. If the relay fails, no power reaches the element even though the element itself is good. This is the most expensive component in the chain and the least likely to have failed — which is why it’s tested last.
Symptoms:
No heat at all, with the element, thermostat, and high-limit all testing good
Error codes displayed
Erratic behaviour — heat sometimes, not others
Multiple functions affected
How to test it:
This requires the machine to be powered with the panel open, which carries live-mains risk. With the machine running a heat cycle, test for voltage at the element connector with a multimeter set to AC volts. Voltage present means the board is working and the fault is downstream. No voltage means the board isn’t switching the element on. If you’re not confident working with live mains voltage, don’t attempt this — call a technician or replace the board by substitution.
Cost: $60–$230 for the part, $180–$585 installed.
Repair or Bin? Usually bin on a machine over eight years old. The board is the one heating fault where replacement wins.
6. Cold Water Supply
Why it stops the machine heating: The dishwasher fills from the hot tap. If the hot water isn’t reaching the machine — because the supply is off, the valve is faulty, or the machine is connected to cold only — the element may not be able to bring the water up to temperature within the cycle time.
Symptoms:
Dishes come out wet and cold
The machine runs a full cycle but nothing gets hot
Performance much worse in winter
The machine works better when the hot tap has been run first
How to test it:
Run the hot tap at the sink for 30 seconds and confirm it’s hot. Check the inlet hose connection under the sink — is it connected to the hot supply? Check the inlet valve is fully open. Run a cycle and open the door mid-wash to feel the water temperature.
Cost: $0 to $50.
Repair or Bin? Repair. Free, and it’s the most commonly overlooked cause.
Which Symptom Points To Which Fault
What you’re seeing Likely cause
No heat at all, any cycle Failed element, thermostat, or high-limit
Heat sometimes, not always Intermittent thermostat or control board relay
No heat, machine is older and cycle runs long High-limit thermostat tripped by scale
No heat, but the element tests good Thermostat, high-limit, or control board
Heats but dishes still wet Drying fault — check rinse aid first
Burning smell during heat phase Scaled element or overheated wiring
Works better in summer Cold water supply or scaled element
Repair vs Replace: The 50% Rule
If the repair costs more than 50% of the price of a new equivalent dishwasher, replace it.
Typical repair costs:
Fault DIY part cost Installed cost Verdict
Cold water supply $0 $0 Repair — check the tap first
Scaled element $0–$20 (descaler) $100–$200 Repair — descale
Failed high-limit thermostat $10–$25 $80–$180 Repair
Failed thermostat $20–$50 $100–$200 Repair
Failed heating element $25–$75 $150–$350 Repair on a machine under 8 years
Failed control board $60–$230 $180–$585 Usually bin on an older machine
New dishwasher cost: $400–$1,500, typically around $1,000 installed.
When to repair:
The fault is the element, thermostat, high-limit, or water supply — which covers most cases
Machine is under 8 years old
Repair cost is under half the new machine cost
When to bin:
The control board has failed on a machine over 8 years old
The machine is past its expected lifespan
Multiple faults at once
Repair cost approaches half the new machine cost
The reassuring part: an element or thermostat repair is $150 to $350 installed — comfortably under the 50% line on any machine under ten years old. Only the control board changes the maths.
What You Can Safely Do Yourself
Safe DIY checks and repairs:
Check the hot water supply at the tap
Check the inlet hose connection and valve
Access and test the heating element with a multimeter
Test the thermostat for continuity
Test and reset the high-limit thermostat
Inspect and descale the element
Test the temperature sensor on models with a separate sensor
Replace the element, thermostat, or high-limit thermostat
Technician required:
Control board relay testing on a live board
Control board replacement
Any repair involving the mains wiring
Internal electrical testing
Safety note: switch off the power at the circuit breaker and shut off the water supply before removing any panel. The heating element operates at mains voltage and reaches high temperatures — never test it with the power connected unless the procedure specifically requires it. The element may be hot even after the cycle ends. Let the machine cool before opening it. Live mains testing of the control board is not a DIY test for everyone; if you’re not confident, don’t do it.
FAQ
Why is my dishwasher not heating the water?
The most common cause is a failed heating element, followed by a failed thermostat. Before testing either, confirm the machine is getting hot water from the supply — a cold fill or a closed valve produces the same symptom for free.
Why do my dishes come out wet?
That’s usually a heating fault rather than a drying fault. The drying phase relies on residual heat in the dishes; if the water never got hot, the dishes can’t dry. But check the rinse aid too — an empty rinse aid produces the same symptom on a perfectly working machine.
How do I test a dishwasher heating element?
Unplug the machine, access the element terminals, and test resistance with a multimeter. A good element reads a low resistance — typically 10 to 30 ohms depending on the model. An infinite reading means it has burned out.
Why is my Whirlpool dishwasher not heating?
The same circuit applies across brands. On a Whirlpool, check the element first, then the thermostat, then the high-limit. Whirlpool machines commonly show a high-limit trip when the element has scaled up — so if the high-limit has failed, descale the element before replacing it.
Why does my dishwasher heat sometimes but not always?
An intermittent thermostat or a failing control board relay. It can also be a water supply issue if the hot water reaches the machine inconsistently. Note which cycles fail before testing.
Why does my dishwasher smell like burning when it heats?
A burning smell from the heating circuit usually means the element has scale that’s overheating, or a wiring connection is overheating. Stop using the machine and inspect the element and wiring before running another cycle.
How long does a dishwasher heating element last?
Typically 7 to 12 years, depending on water hardness and usage. Hard water shortens element life significantly because scale causes localised overheating.
Is it worth repairing a dishwasher that won’t heat?
Usually yes on a machine under eight years old. An element or thermostat is $150 to $350 installed, well under the 50% line. A control board on an older machine is the exception.
Where to Go Next
This post has covered the full heating circuit and the decision framework for repair versus replacement. Depending on your situation, one of these is your next step:
If you’ve tested the element and it’s good, or the machine heats intermittently, the complete guide walks the circuit in order — element, thermostat, high-limit cut-out, and control board relay — with the multimeter tests, expected readings, the descaling procedure, and the repair-or-bin verdict for each component.
Get the Dishwasher Heating Element Repair Guide — $7.95 →
If the machine runs and heats but the door is leaking, that’s a separate fault with its own diagnostic sequence.
Get the Dishwasher Door Seal Repair Guide — $7.95 →
If the water is the problem rather than the heat — standing water in the bottom — that’s a drain fault.
Get the Dishwasher Not Draining Guide — $7.95 →
If you want the cost comparison across every dishwasher fault — not just heating — the repair-vs-replace hub covers the full picture.
Dishwasher Repair vs Replace: What Each Really Costs →
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