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Parts for Whirlpool WED5100VQ1 Dryer - AppliancePartsPros.com

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I guess the timer is causing the buzzing, [/COLOR]
Sorry but you have to know for sure what is causing the buzzing.

[COLOR="Blue"]but Why would dryer get hot when it is not turned on?[/COLOR]
This one is strange so all I can do is point you in certain directions.

The first problem I have is that you get heat without the motor running.
The motor has two centrifugal switches on it. They activate when the unit gets close to operating speed.
One of them switches in the heater so if you have heat with no drum rotation perhaps the switches are activated when they should not be.
The other centrifugal switch switches out the motor's start winding. If left in circuit when the motor is running it would over heat the motor.
So if it is activated you do not have a start winding and the motor can sit there and buzz.

And now for the kicker.
The start relay contacts should be open so the motor should not be getting any voltage and therefor should not be buzzing.

I would start by checking the motor's centrifugal switches.
Perhaps thre are two problems in the unit.