Samsung Dryer Won't Stop — Top Causes
First feel the exhaust air. If it is still hot after the cycle should have ended, the dryer is heating continuously — a safety issue usually caused by contaminated moisture sensors, a bad thermistor, or a heater relay stuck on the board. Cool air with continued tumbling is a stuck timer or motor relay.
Two very different "won't stop" faults#
A Samsung that will not stop is really two problems, and the exhaust temperature tells them apart in seconds. In the dangerous version the dryer keeps heating and tumbling; continuous heat can overheat the cabinet and ignite lint, so it needs prompt attention. In the annoying version the heat has stopped but the drum keeps turning — often a stuck relay, a board timer fault, or simply the Wrinkle Prevent feature tumbling periodically after the cycle.
Feel the air first: still hot means the heating version and a real safety concern, cool means the tumble-only version. Samsung also enforces a maximum cycle limit of a few hours, so a dryer that finally quits after three to five hours is telling you its sensors never confirmed the load was dry.
The tell: continuous heat points at the moisture sensors, thermistor, or heater relay, while endless cool tumbling points at the board timer or a stuck motor relay.
Causes ranked by likelihood#
| Likely cause | What you see | Fix |
|---|---|---|
| Contaminated moisture sensors — most likely (heating) | Runs for hours, exhaust still hot | Clean both sensor bars with isopropyl alcohol and a light 220-grit scuff so they read dryness again. |
| Thermistor misreading | Continuous heat; wrong temperature control | Test the thermistor and replace it if it reports incorrectly. |
| Heater relay stuck on the board | Heat will not shut off at all | Replace the control board when the heater relay stays closed. |
| Board timer or motor relay stuck (cool) | Tumbles without heat after the cycle ends | Test the board and motor relay for a stuck-on condition. |
| Wrinkle Prevent mistaken for a fault | Brief periodic tumbles after completion | None needed; turn off Wrinkle Prevent if you do not want it. |
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Check it yourself, in order#
- Feel the exhaust air first: still hot is the dangerous heating fault, cool is the tumble-only fault. Do not leave the dryer running unattended either way.
- If it eventually stops after three to five hours, the maximum-time safety limit is ending it — the moisture sensors are not confirming dry.
- Clean both moisture-sensor bars inside the drum with isopropyl alcohol and a light 220-grit scuff.
- If heat still will not shut off, test the thermistor and then the heater relay on the board.
- For cool-air tumbling that will not end, suspect the board timer or a stuck motor relay.
- Rule out Wrinkle Prevent, which tumbles periodically after the cycle by design.
Safety note#
A dryer that keeps heating after the cycle should have ended is a genuine hazard, because prolonged overheating can ignite lint. Do not leave it running unattended, unplug it if the exhaust stays hot, and clear the lint filter and vent before returning it to service. Until the heating fault is fixed, treat the dryer as unsafe to run and do not rely on the maximum-time limit as a substitute for the repair.
Safety First — Know the Risks
Gas dryers carry carbon monoxide and explosion risk. Even electric dryers involve 240V circuits that can deliver a fatal shock. Our techs are licensed and insured — let them handle the risk.
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Repair or replace?#
Cleaning the moisture sensors costs nothing, and a thermistor is an inexpensive part, so most won't-stop faults are a cheap fix. A failed control board on an older dryer is the pricier case where a repair-or-replace decision belongs. A technician can confirm the sensor versus the board in one visit. Book a diagnosis for an upfront quote.
Senior Appliance Repair Technician · 15 years experience
EPA-certified technician with 15 years of experience specializing in refrigerator and cooling system repairs.
