I have a problem drying clothes when the timer is set to “DRYNESS” (7:00 on the timer dial). The machine operates OK but the timer does not move clock-wise and turn off when the clothes are dry. If I set the timer knob to 30 minutes (3:00 0n the timer dial), everything works properly. I think I need to replace the sensor part #30 (AP3094143).
Can anyone concur with this? Is there another item I should consider replacing?
Here are the parts
Replacement parts for WHIRLPOOL LET7848AQ0 | AppliancePartsPros.com
Here is the wiring diagram
http://www.servicematters.com/docs/wiring/Wiring%20Sheet%20-%203396203.pdf
Have you tried cleaning the sensor strips.
The way it works is that moisture from the clothes creates a circuit path between the sensor strips. The electronic control (Item 51 in Section 2) senses this and holds the timer off. When the clothes are dry there is no longer any moisture so the circuit path is open and the circuit board then advances the timer. If there is dirt/residue build up between the sensor strips the machine always thinks the clothes are wet.
Clean them with a damp cloth and dry thoroughly.
Or clean them with isopropyl alcohol just be sure that the solvent fumes have dissipated as they are flammable.