The short answer
A cycle that stops early or never advances on the FDG line is usually the machine protecting itself or mis-sensing the load, not a failed control. On this page the vent leads: nearly every cycle complaint on a dryer is an airflow complaint underneath. An automatic cycle ends on dryness, not on time, so a load that keeps coming out damp after two minutes of tumbling is a sensing or airflow story.
What an owner actually observes on the FDG line
- The timer never seems to move on an automatic cycle — Automatic timers only advance once the load is drying, so a slow cycle points at airflow or heat.
- It stops every time the door is knocked — An intermittent door switch. The machine is obeying the interlock exactly as designed.
- NEAR MISS — the drum turns but there is no heat at all — Then this is a heating fault rather than a cycle fault, and the checks are different: element, fuse and gas valve rather than sensing and venting.
The ranking for the FDG line, likeliest first
- The vent run is restricted or blocked — Ranked first on the FDG line because restricted venting causes every symptom on this page at once — long cycles, thermal trips and hot damp loads — and because it is the one cause that is also a fire risk.
- A thermal cut-out or cycling thermostat is opening — Cycling thermostats and one-shot cut-outs both respond to heat the machine cannot shed. Treat them as a symptom of restriction, not as the fault.
- The moisture sensor is coated or mis-reading — Wiped clean with a little vinegar, sensor bars usually recover. The fault looks like a broken timer and is neither electronic nor expensive.
- The load is too big, too mixed or too wet — Last, and free: rerun a small, single-fabric load before assuming the machine is at fault.
The diagnostic order, and the reason for it
- First — disconnect the vent at the machine and look at the duct and the outside hood — Air should leave the hood strongly with the machine running. A lint-packed duct makes the machine run long and trip hot.
- Then — note whether it stops hot and restarts after it cools — That is a protective cut-out opening. Clear the vent first: replacing the device without fixing airflow simply repeats the failure.
- Only then — wipe the moisture sensor bars inside the drum — A little vinegar on a cloth removes softener film. Coated bars read a wet load as dry and stop the cycle in minutes.
- STOP here if the next check needs a panel off or a meter on live terminals — Everything above can be done with nothing dismantled; past it the checks need test equipment.
Read this before any panel comes off
Safety
Unplug the dryer or switch off its breaker before any panel comes off — a capacitor can hold a charge after the power is off, and the heater terminals stay live whenever the machine is connected. If yours is a gas model and you smell gas: do not switch anything on or off, leave the building, and call the gas utility or emergency services from outside; do not look for the leak yourself. Never run the machine with the vent disconnected into the room, and never bypass a thermal cut-out to get a load finished.
When it stops being an owner job
Call when the vent is clear, the sensor is clean and a timed cycle still fails, because the next checks are continuity on the thermostats and the door switch. On the FDG line, call rather than continue if the rear panel has to come off. Call immediately if there is a burning smell, a scorched load or a machine that keeps tripping its cut-out after the duct has been cleared — repeated overheating is how dryer fires start.
Other faults covered for the FDG line
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
