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Replacement parts for Whirlpool IED4400SQ0 29"ELECTRIC DRYER | AppliancePartsPros.com

See the attachment for the tech sheet.

[COLOR="Blue"]There is 240V across the main power wires[/COLOR]
I am assuming that tis was checked at the terminal strip in the unit.

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Both the high and low limit thermostats have 120V at each wire and 0 ohms across the terminals for each thermostat.[/COLOR]
I am not sure what you are calling the low limit?
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The heating element doesn't appear to be physically damaged.[/COLOR]
It is best to actually measure the heating coil.

Unplug the unit and set it to mid-cycle heated timed dry then attach one meter lead to L1 and leave it there. Then work your way back through the heater circuit. Everything should be 0 ohms till you get to the heating coil then one side of the coil will be 0 ohms and the other 8 to 12 ohms.

If all OK then you know that either you have a bad wire or a problem with the motor's centrifugal switch.

[COLOR="Blue"]Also, I'm not sure which wire in the standard 3-wire grey cable is L1 or the black one?[/COLOR]
Just measure them back from the terminal strip.

[COLOR="Blue"] Someone also mentioned to me about a heater switch on the motor. Could this be the centrifugal switch?[/COLOR]
Yes, one of them is for the heater.
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Or possibly a problem w/ the timer?[/COLOR]
Yes, Timer Switch 2 on the wiring diagram.

[COLOR="Blue"]I checked the cycling thermostat and is 0 ohms across the larger terminals and about 8 across the smaller terminals. Is that good?[/COLOR]
Yes