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Replacement parts for WHIRLPOOL TEDL640DQ1 ELECTRIC DRYER | AppliancePartsPros.com

See the attachment for the wiring diagram.

No heat can be a number of things: power, heating coil blown, open thermostat/thermal cut-off, timer contacts or the motors centrifugal switch.
I listed them in the order they should be checked.

Try flipping the breaker off/on slowly a couple times.
Sometimes you can loose half the line without actually tripping the breaker.
The motor etc run off of 120 volts but the heating coil requires 240 volts.
If this does nothing, check the voltage at the plug
L1 to L2 should be 240 volts
L1 to Neutral and L2 to Neutral, both should be 120 volts.
If OK
Unplug the unit and check the wires at the terminal strip in the machine to make sure none are loose or burned out
If OK
Check the power at the terminal strip.
[COLOR="Red"]Be careful as 240 volts is lethal !!! [/COLOR]

The heating coil, thermostats, high limit cut-off and the timer contacts can be checked with the unit unplugged using ohms. This is much safer than messing with the unit plugged in.

If the thermal cut-off is blown get back to us as there are other things that should be checked before replacing it.

Cannot really say how much technical expertise is required.

Here is a good link with basic dryer repair info.
http://www.applianceaid.com/dryers.html

Also there are lots of videos on Yahoo.
Your unit is made by Whirlpool.

If you do not own a meter, I would suggest you purchase a one. You can get a decent digital multimeter for under $20.00. You do not need fancy though it is nice if the leads are a couple feet long.
If it saves ordering one unnecessary part it has paid for itself and you end up owning a useful tool.
Most places will not let you return electrical parts so if you order it, you own it.
A couple things to watch when measuring ohms and continuity
1. Always remove power from the machine otherwise you could blow your meter.
2. Always disconnect at least one side of any device you are checking. This eliminates the possibility of measuring an alternate/parallel circuit path.
3. When checking for closed contacts and continuity use the lowest scale (Usually 200 ohms). Then try higher scales. This scale is 0 to 200 ohms so if the device you are measuring is 300 ohms this scale would show an open circuit which it is not, you are just measuring outside the scale's dynamic range.

There is a good STICKY at the start of this forum about it's use.