Microwave completely deadwhat to check
No display, no light, no fan. On a microwave this is very often a safety system working as designed, and fitting a new fuse is the wrong repair.
Take care
Get a qualified appliance engineer to look at your microwave
We do not pass enquiries to a repair firm, so there is no form here. When you book a qualified appliance engineer, tell them the make, the model and the exact code or message on the display, and ask whether they carry parts for this make — that is what turns one visit into a repair rather than a quote.
What this means
A microwave with nothing on the display, no cavity lamp and no fan has almost always blown its internal fuse, and the reason it blew is the interesting part. Behind the door is a chain of switches — a primary interlock, a secondary or door-sensing switch, and a monitor switch whose only job is to watch the primary one. The standard these appliances are built to in the UK has a name for that arrangement, a monitored door interlock: an interlock system that incorporates a supervision device. What the supervision device does when it catches a problem is deliberate destruction.
Whirlpool put it plainly in their service documentation: the monitor switch is provided to monitor the operation of the primary interlock switch, and if the primary switch fails to operate when the door is open, the monitor switch will form a short circuit across the supply and the fuse in the oven will blow. Read that again, because it inverts the usual assumption. The appliance is not broken in the sense of having failed; it has detected that it could no longer guarantee it would stop making microwaves when you opened the door, and it destroyed its own power supply rather than take the chance. That is why the popular internet remedy is dangerous rather than merely inadequate.
Fitting a fresh fuse restores power to an appliance whose interlock chain is unproven, and Whirlpool are explicit about what to do instead: if the fuse is blown due to the failure of the primary interlock, repair the failed mechanical parts and replace all the interlock switches. Their 2020 documentation says the same in current wording — these switches cannot be adjusted, and all of them should be replaced if any one is found to be defective.
What causes it
| Cause | What is actually happening | How likely |
|---|---|---|
| Monitor switch has blown the fuse on purpose | The primary interlock failed to open with the door, so the monitor shorted the supply and destroyed the fuse deliberately. | Common |
| Door hinges or latch have gone out of position | Whirlpool list a loose door hinge or a poorly adjusted door as a cause of the fuse blowing, because the latch pins then miss the switches. | Common |
| No supply reaching the appliance at all | Named first in the manufacturer symptom table: plug not making contact in the socket, or no power at the socket. | Common |
| A component has failed short and taken the fuse with it | Whirlpool list a shorted lamp filament and a shorted high-voltage transformer as causes of the same dead appliance. | Occasional |
Can you fix it yourself?
Stop — this needs an engineer
What it costs to fix
Typical repair cost
£70–£140
Time on site
15 minutes
Typically £70 to £140 for a visit plus an interlock switch set, the switches themselves being a few pounds each. Frequently more than a basic countertop microwave is worth, which is worth knowing before you book.
Typical UK prices including parts and labour, updated September 2026. Your quote may differ.
Own this appliance and had this code? . Nothing is published until a person has read it.
Related microwave fault codes
- Is my microwave leakingGet it checkedThere is a published UK limit and a real test for this, and the door seal is what usually fails it. What there is not, is a way to check it at home.Related: door interlocks and containment
- Door will not openGet it checkedThe button presses and nothing releases. On a microwave the latch is part of a safety chain, so forcing it is worse than it looks.Related: door interlocks and containment
- Not heating but runningGet it checkedThe light is on, the turntable is going round and the food comes out cold. This is the classic microwave failure and none of it is an owner repair.Related: same brand
- Sparking inside the microwaveGet it checkedBright arcing and a scorched smell. Look at the small panel on the cavity wall before you run it again — a burnt waveguide cover is the usual answer.Related: same brand
- Turntable not turningUsually simple to fixFood heats in patches and the plate sits still. Almost always the coupler, the roller ring or a plate seated wrongly, and mostly fixable in the cavity.Related: same brand
- Ran the microwave emptyGet it checkedRunning a microwave with nothing in it is the one thing an owner can do that reliably damages it, and the service manuals put it in capitals.Related: same brand
Related guides
Common questions
Can I just replace the internal fuse myself?
It is the thing most likely to be suggested to you and the thing the service manuals most clearly warn against. If the monitor switch blew that fuse, the interlock chain is unproven, and a new fuse re-energises the appliance without addressing that. Whirlpool say to repair the mechanical parts and replace all the interlock switches. There is also the capacitor, which stays charged after the plug is out.
It died the moment I slammed the door. Is that a coincidence?
Almost certainly not, and it is the classic version of this fault. A hard door movement is what knocks the latch and the switch timing out of step, and the monitor switch reacts to the switches operating out of sequence rather than to anything electrical.
Is it worth repairing?
On a built-in model, usually yes, because replacing it means matching a housing. On an inexpensive countertop machine the labour alone can approach the price of a new one, and that is a fair reason to replace rather than repair — but replace it, rather than running it with a fresh fuse and unproven interlocks.
Technical review
Not reviewed by an engineer
No engineer has read this page. Severity follows what the manufacturer publishes, and we would rather tell you that than let a byline imply a sign-off.
Sources and how we verified this
We establish the facts from the sources below and then write the explanation ourselves. We do not copy manufacturer wording and we do not host their manuals.
- Manufacturer technical and service documentation
- Trade body guidance
This page has not been reviewed by an engineer, and we would rather tell you that than imply otherwise. The severity rating follows what the manufacturer publishes: where they say isolate the appliance and call someone, so do we.