I've been reading the previous 50 or so posts tonight---and noticed several visitors to the forum had a common "problem" with their dryer---which uses a MOISTURE SENSOR.
The complaint was identical:
"Laundry doesn't always dry" (and the vent system was ruled-out)
The responses were similar:
"Avoid small loads in dryers that have/use MOISTURE SENSORS"
"For small loads---use the TIME DRY cycle"
There is a solution---and it's a very simple one.
Some years back---I had an older lady (widow)---that contacted us regarding her LG dryer.
Her complaint was that the laundry was not dry at the end of the cycle.
Also---the cycle run time/duration was rather short (cycle ended far earlier than initial time displayed).
In her case---she does not wash/dry large loads at all---and rarely does she even have medium sized loads to wash.
On LG dryers---the MOISTURE SENSOR ("bars") are located at the front of the dryer---on the LINT FILTER HOUSING.
If the dryer is dead-level---which hers was---a small load of laundry will tumble in the GIANT DRUM and very erratically come into contact with the MOISTURE SENSOR.
By raising the REAR LEVELING LEGS about an inch---this forced the tumbling small load of laundry to remain at the *front* of the dryer---continually falling/contacting the MOISTURE SENSOR.
On dryers (other brands) in which the sensors are positioned at the rear/back of the drum---simply raise the *front* leveling legs to get the same result.
Technicians can demonstrate to the customer by running the dryer with 2 or 3 small pieces of clothing---laundry will either tumble at the rear of the drum or near the center (in an LG dryer--for example).
Explain to the customer---the MOISTURE SENSORs function and that wet/damp laundry *must* continually come into contact with the sensor (show the customer the location of the sensor).
After adjusting the legs---the customer/owner will notice the laundry moving toward the SENSOR location with 30 seconds of starting the cycle---and remain at that location in the drum for the duration of the cycle.
Source: Dryers With Moisture Sensors