Residue from dryer sheets and fabric products can insulate moisture-sensor bars. Locate the model's bars, clean them only as the manual permits and compare Sensor Dry with Timed Dry before replacing parts. First, confirm the load contacts the sensor and contains similar-weight items.
What this covers
- A dryer with automatic moisture-sensing cycles
What it does not cover
Try in this order
0 of 10 completedEstablish the exact starting state
ReversibleConfirm the load contacts the sensor and contains similar-weight items.
Separate the fault or decision boundary
ReversibleCompare a timed cycle; normal timed drying with early sensor-cycle stops points toward load contact or sensing.
Apply the narrowest correction
ReversibleClean and dry the accessible sensor bars with the approved method and correct load size/mix.
Find the sensor bars and check they touch the load
ReversibleLook inside the drum, near the door opening, for two thin metal strips. Confirm the load reaches them, since a very small load or a lot of bulky items can keep the clothes off the bars and end the cycle early.
Compare a timed cycle with the sensor cycle
ReversibleRun the same load on a timed cycle. If it dries normally on time and ends too early on the sensor cycle, the sensor bars or the load mix are the cause rather than the heater.
Clean the bars with the approved method and dry them
ReversibleWith the dryer off and cool, wipe the bars with a soft cloth and a little rubbing alcohol or the cleaner your manual recommends, then let them dry. Then run a damp test load on Sensor Dry and check that the time stays stable.
Find the sensor and check it is clean to the touch
ReversibleLook inside the drum near the lint filter for the metal strips or the sensor surface. A visible film, usually from dryer sheets and fabric softener, is the usual sign that the sensor is insulated from the wet laundry it is meant to read.
Wipe with a soft cloth and the cleaner your manual allows
ReversibleBosch's method is mild soap and warm water on a soft cloth, followed by a clean damp cloth and thorough drying, or a damp cloth with a little white vinegar. Do not use steel wool or an abrasive pad.
Test with a sensor cycle against a timed cycle
ReversibleDry a normal load on the sensor cycle and check it against a timed cycle. If the sensor cycle now ends with dry clothes and roughly the expected duration, the film was the problem.
Verify before escalating
ReversibleRun a controlled damp load on Sensor Dry and confirm the remaining-time behavior stabilizes.
By brand
What LG and Bosch say about cleaning the sensor
Both makers tell owners to clean the sensor; they differ on how it is described and what to wipe it with, so follow your own manual where it is specific.
- LG
- LG's guide says to regularly clean the surface of the humidity sensor so it is not contaminated. A dirty sensor can fail to measure the moisture in the load correctly, which shows as excessive drying or incomplete drying, and LG's page names no cleaning product or fixed schedule.
- Bosch
- Bosch places the moisture sensor inside the drum, typically near the lint filter, and says to wipe it with a soft cloth and mild soap in warm water, then a clean damp cloth, drying it thoroughly. It also allows a damp cloth with a little white vinegar, and says cleaning every few months keeps the dryer performing.
- What both point to
- Neither maker tells you to scrape or scour the sensor. A soft cloth is the common instruction, which matters because the sensor is a thin metal surface, not something to abrade.
Stop boundary
When this stops being a self-service repair
- !Service is appropriate if normal loads still end within minutes after cleaning the bars and a timed cycle dries the same load correctly.
Evidence ledger
Sources behind this answer
Exact questions
Common questions about “Clean dryer moisture-sensor bars when cycles end too early”
What do the moisture-sensor bars do?+
They measure the moisture in the clothes as they touch the bars, so the dryer can stop when the clothes are dry.
Why do the bars get coated?+
Fabric-softener sheets and some laundry products leave a thin film that insulates the metal, so the sensor reads dry too soon.
How often should I clean them?+
A few times a year is common advice, and more often if you use dryer sheets regularly.
Can I use steel wool?+
No. Abrasive pads can scratch the metal and shorten its life, so use a soft cloth.
Do dryer sheets really foul the sensor?+
Makers do not name dryer sheets specifically, but LG says a contaminated sensor can fail to measure moisture and lead to excessive or incomplete drying. A film from any fabric product on a metal surface has that effect.
The dryer ends cycles early with damp clothes. Is it the sensor?+
A contaminated sensor can cause incomplete drying, which fits. Compare a timed cycle with the sensor cycle after cleaning: if the timed cycle dries the load and the sensor cycle did not, the sensor was reading wrongly.
Can vinegar damage the sensor?+
Bosch's own instructions allow a damp cloth with a little white vinegar, so it is a maker-sanctioned method. Rinse with a damp cloth and dry thoroughly afterwards.
Where are the sensor bars on the dryer?+
They are two metal strips inside the drum near the door opening or on the lint-screen side. The manual will show the exact position for your model.
What should I clean them with?+
Wipe with a soft cloth dampened with rubbing alcohol or a mild vinegar solution, then dry. Avoid abrasive pads that scratch the coating.