Here are your parts
Replacement parts for MAYTAG AED4475TQ0 29" Electric Dryer | AppliancePartsPros.com

Here is the wiring diagram
http://www.servicematters.com/docs/wiring/Tech_Sheet_01_20_2010/Wiring%20Sheet%20-%20W10185979.pdf



[COLOR="Blue"]I checked the start switch and found that potential voltage drops when button is depressed and no voltage is seen on other pole.[/COLOR]
Was the voltage across it 120 volts?
When open one side should read 0 volts, the other should be 120 volts, when referenced to Neutral.
Your test is telling you that the switch is closing.
Re: It sees the 120 volts as the voltage is across the switch (open circuit). When it closes the voltage drops to 0 because the resistance drops to 0 ohms and you cannot have voltage across 0 ohms as it is a dead short.
Note: That the 120 volts on the left hand side of the switch is not necessarily coming through the motor circuit. It could be coming through the thermostat heater.
I hope the above makes sense.

When you checked the voltage did you have 120 volts on L1 to Neutral and the L2 to Neutral. It is the L1 to Neutral that is the motor voltage. This is important because sometimes you can loose half the line without actually tripping the breaker.

The thermal fuse for the motor is the one on the blower (Item 23 in Section 3). When checking for resistance always disconnect one side of the device you are checking. This ensures that you are not reading an alternate/parallel circuit path.

You still have the motor windings and the timer contacts to check.
Also I would double check the door switch.

Here's the update. The dryer is my aunts and she found a friend that works for the sears maint. group, not with dryers, but still a sharp guy. Before he got there I rechecked the door switch and the thermal fuse, both in working order. He went through about the same steps checking everything and didn't really find anything new. Niether one of us know anything about how to check the timer except to find that it has power in. However where we expected to find power out we found low voltage (around 30V). The entire time we checked and rechecked line voltage and found it to be good. We didn't get a chance to check motor windings.

Problem still remains.

Does the drum light work.
If it does then you are getting at least 120 (L1 to Neutral) into the unit.

The 30 volts you see is probably just ghost voltage.

Timer contacts can be checked the same way you check a switch.
Unplug the unit set the timer to mid-scale timed dry.
The contacts for start/motor are B and C
Remove the B wire from the timer and measure across B/C.
Should be 0 ohms.

One way to check it out is:
Unplug the unit.
Set it to mid-scale timed dry.
Attach/tape one lead of your meter to L1 (at the meter or the end of the power cord) and leave it there.
Then work your way back through the motor circuit a component at a time.
OR
If you do this and check to the W or W-R of the push to start switch and see 1 to 2 ohms you know that the timer contacts, the thermal fuse and at least one of the motor windings are OK.