The short answer
A dishwasher that will not start is usually unpowered or unlatched rather than broken. Look for any light on the panel: lit means the machine is refusing, dark means the spur switch and the breaker come first.
What you actually see and hear
- Panel lights but the cycle never starts — It has power and is declining - the door, a lock or a delay.
- Completely dark — Supply. The spur, the breaker or the connection behind the cabinet.
- It beeps or flashes on pressing start — Reporting a condition, most often the door.
- It starts only when the door is pushed — The latch, which has named its own fault.
- NEAR MISS - it starts and stops part-way — That is a cycle fault and a different question.
Causes, most likely first on this machine
- Spur switch or breaker — First on a fitted machine. The switch is often in a neighbouring cupboard and gets knocked, and the fault looks like a dead appliance.
- Door latch and its switch — Second. It operates every cycle on a light door and wears out of alignment while still looking shut.
- Control lock or delay start — Third, and free to rule out. Flush panels are easy to set by accident.
- Water supply valve closed — Fourth. Many machines will not begin a cycle they cannot fill, and a valve closed after plumbing work reads as a no-start.
- Control board, harness or thermal device — Last. Real but least likely, and each needs a meter.
Check in this order, and why
- Look for any light, tone or symbol on the panel — Lit or dark splits the ranking in two.
- Find and check the spur switch and the breaker — The most common invisible cause on a fitted machine.
- Close the door deliberately hard and press start — If it runs, the latch is the fault.
- Check the isolating valve under the sink is open — One turn, and it explains a machine dead since plumbing work.
What an owner can safely check
- Switch the spur off and on, then press start — It proves the switch and clears a hung control at once.
About 5 min
- Check the breaker and the connection behind the cabinet if the panel is dark — Do this before assuming a board has failed.
About 10 min
- Hold the marked button to clear any control lock — Look for a padlock symbol.
About 5 min
- Check whether a delay start is counting down — A machine on delay looks inert and is fine.
About 5 min
- Open the isolating valve under the sink fully — Especially after any plumbing work.
About 10 min
- STOP HERE before pulling the machine out to test the door switch or the board — Live work in a wet cabinet.
Before you open anything
Safety
Unplug the appliance or switch off its breaker before removing any panel - a capacitor can hold a charge after the power is off. A dishwasher sits in a wet cabinet with a live connection behind it, so switch off at the breaker before pulling it out and close the isolating valve under the sink before touching any hose. A plastic tub holds heat, so let a hot cycle cool before reaching inside.
When to call a technician
Call when the panel lights, the door latches firmly, no lock or delay is set, the water is on and the machine still will not begin - that leaves the door switch, the inlet valve or the control. Call an electrician instead if the machine is dark with the spur and breaker both on, because the fault is then in the fixed wiring. Call immediately if the breaker trips again when you reset it.
Nearest pages of this class
What this page does not cover
This page is written for the plastic-tub built-in dishwasher class, not for one family or model line. Where a brand- or model-specific page exists for your unit it is the more specific answer and it is linked above, so go there first if your machine is named. What is deliberately not here: spray arm and pump part numbers, heater ratings, door spring tensions and control diagnostics, all of which differ by family and belong on the page for that family.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
