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Replacement parts for WHIRLPOOL LEB6400LW0 RESIDENTIAL DRYER | AppliancePartsPros.comSee the attachment for the wiring diagram
Unplug the unit and disconnect it from the vent system.
Now try a run.
If it now dries OK odds are the vent system needs checking/cleaning.
Be sure to check that the louvers on the outside of the house open correctly.
If you do not want any lint in the house.
Take a pair of pantyhose.
Put one leg into the other and then attach this to the dryer's vent.
Leave enough room so the pantyhose can balloon out like a windsock.
Both the above will let you check the temperature and the air flow.
Your main thermostat (Item 8 in Section 3) should open at 155 degrees F and re-close at 130 degrees on high heat so your exhaust temperature should be in this range on high heat.
If you have a thermometer check it.
You will see that the main thermostat is 4 wire. Two of these are the heater contacts the other 2 is a built-in heater (4,800 ohms). The heater adds heat to the thermostat which causes it to cycle more often reducing the units main heater output.
Perhaps it is always on for some reason.
Unplug the unit and one wire to the thermostat's heater. tape the wire up so that it cannot short to anything and then give it a try.
Check your lint filter sometimes it can get coated with fabric softener residue and has to be cleaned with soap and water.