The short answer
A T dryer that will not start is usually not getting the permission it needs rather than failing: a door that is not latched, a control lock, or a supply that is only half there. The table below carries two model codes for this family, close enough in build that the layout described here holds across both.
What you observe on these models
- Nothing at all — no lights, no sound — No power. Breaker, outlet, or the cord connection, and on an electric machine possibly only half the supply.
- The panel lights but pressing start does nothing — Power is fine. The door latch, a control lock or a delay is refusing the cycle.
- A hum with no drum movement — The motor is energised and something is stopping it — a broken belt leaves the motor free, a seized drum stops it dead.
- It starts and stops again within a second or two — The start circuit is engaging and dropping out, which points at the motor start components or an overload.
- The door does not click firmly when closed — The door switch is the interlock. A door that closes without latching is indistinguishable from a dead machine.
- It runs only while the start button is held — The start circuit is not latching in, which is a control or motor circuit symptom rather than a door one.
Causes, most likely first on the T family
- The door is not latching, or the door switch is not making — First, free, and the commonest cause. Close the door firmly and listen for a positive click before anything else is suspected.
- A control lock or a delay start is set — Ranked high because it costs nothing: look for a lock or key symbol and hold the marked button until it clears.
- The supply is missing or only half present — Switch the breaker fully off and back on rather than just looking at it — a partly tripped breaker is easy to misread.
- The belt has broken — Fourth, and easy to confirm: with the power off, turn the drum by hand.
- The motor, its start switch or the control has failed — Last, by elimination only, and the one candidate on this list that is never an owner repair.
Check in this order, and why
- Press start and listen for one second — Silence, a click, or a hum. Those three outcomes split this list into branches that barely overlap, and the test costs nothing.
- Close the door hard and listen for the latch — A positive click is what the interlock needs. Check nothing is holding the door a fraction open at the top edge.
- Clear any lock or delay — Hold the button marked with a lock or key symbol until the symbol clears, and cancel any delay that is counting.
- Switch the breaker fully off and back on — Do not judge it by sight. On an electric machine a single lost leg leaves the drum unable to start while the panel still lights.
- Turn the drum by hand with the power off — Unplug first. A drum that spins with almost no resistance has lost its belt; one that will not move at all has seized and must not be run.
Models in the T family — Each code here is pinned to a single build, so match the tag inside your door frame character for character.
Reference| Model number | Family key |
|---|---|
| T21 | bosch:dryer:t |
| T27 | bosch:dryer:t |
Before you open anything
Safety
Isolate at the breaker before anything is opened or the drum is turned, and close the gas valve first on a gas model; a capacitor can hold a charge after the power is off. A breaker that trips again when the dryer is started is reporting a real fault — reset it once, not repeatedly.
When to call a technician
The door, the breaker, the lock and a hand-turn of the drum are the owner checks on these models, and they resolve or explain most no-start calls. The line is the cabinet: door switches, belts, thermal fuses and motor start components all need panels off with the machine isolated and, on a gas model, the gas closed off.
Sources — The symptom-report corpus recorded in this snapshot is what put this symptom on the page for this brand and appliance.
Documented- amazon-reviews — amazon-reviews, fetched 2026-09-02
Other symptoms covered for this family
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
