The short answer
A hum with no rotation means something is energised and stuck, which is a much shorter list than a machine that does nothing at all. On a Bosch dryer it usually means a door switch that is no longer making, or a supply that is not there at all — a dead dryer is far more often a circuit problem than a machine problem. Everything on the owner side of this page is free and takes a few minutes.
What you observe
- It hums when you press start but the drum does not move — Something is energised and is not turning, which narrows it sharply.
- The door needs a push before the machine will accept a start — That is the door switch telling you about itself.
- Nothing at all — no lights, no sound, no response — A completely dead panel points upstream of the machine rather than inside it.
- NEAR MISS — a bang or a noise, then nothing — A noise followed by no rotation usually means a belt has gone, and that is a repair rather than a start fault.
Causes, most likely first on Bosch
- No supply reaching the machine — A tripped breaker, a plug that has worked loose behind the cabinet, or on an electric machine a loose terminal at the block. Ranked first on Bosch: it is the most common cause of a completely dead machine and the only one you can settle without touching the appliance at all.
- A restriction in a path built with very little margin — Filters, small-bore hoses and close-fitting seals are what make this class of machine quiet and efficient. Second on Bosch because the narrow-tolerance paths are the first thing to foul on this construction, and clearing one costs nothing but time.
- A control lock, a delay setting or a paused cycle — Child lock engaged, a delayed start counting down, or a cycle left paused rather than cancelled all give a machine that lights up and will not go. Third on Bosch because it is free to rule out in seconds, it is embarrassingly common, and it belongs high on the list precisely because nobody looks.
- A control board that is no longer commanding the motor — The board takes the start press and closes the motor circuit. Last, and that is the whole point of the order on Bosch: it is the least likely cause and the most expensive, so it belongs after every switch, fuse and supply check above it.
- Body: Bosch builds for quiet, which means tight clearances and fine filtration throughout — and those are the first things to foul, long before anything wears out. The ranking below follows that construction.
Check in this order, and why
- Check what tight-tolerance build means for this machine — First, because it splits the top of the ranking from the rest. Find and clear every filter and screen the machine gives you access to before touching anything else.
- Check the plug and the outlet behind the machine — Second, once that is clean. A plug that has walked out of a large outlet, or a scorched pin, is both a cause and a safety matter in its own right.
- Listen carefully when you press start — Third, and only if the two above told you nothing. Complete silence, a click, or a hum each point somewhere different.
What an owner can safely check
- Cycle the breaker fully off and back on — Push it firmly to the off position first, then back on.
About 5 min
- Test the door with a firm push and start — Hold the door closed with a hand and press start.
About 5 min
- STOP HERE — the next step needs a meter on live terminals — That is exactly where an owner check ends and a service call begins.
Before you open anything
Safety
Unplug the dryer or switch off its breaker before you open the cabinet — a dryer circuit is a high-current circuit and the element terminals stay live at the block until it is off. On a gas dryer, shut the gas valve at the appliance as well, and if you smell gas: do not switch anything on or off, leave the building, and call the gas utility or emergency services from outside.
When to call a technician
Call once the supply is proven, the panel is unlocked and the door latches firmly and the machine still does nothing — that leaves a switch, a thermal fuse, a motor or a board, all on live high-current terminals behind the cabinet. Call straight away if the plug, the cord or the outlet is scorched or warm, and leave that circuit off until someone has looked at it.
Nearest pages of this class
What this page does not cover
This is generalized information for Bosch dryers as a class, not for one product line or one model. Where a line-specific page exists for this brand and appliance it is linked below, and it is the more specific answer — start there if your unit is one of those lines. Deliberately not here: wiring colours, torque figures and part numbers, all of which differ by family.
Links: - [Bosch T Dryer: Will Not Start or No Power](/blog/bosch-bosch-dryer-t-dryer-wont-start) - [Bosch WNA Dryer: Will Not Start or No Power](/blog/bosch-bosch-dryer-wna-dryer-wont-start) - [Bosch WPA Dryer: Will Not Start or No Power](/blog/bosch-bosch-dryer-wpa-dryer-wont-start)
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
