Maytag Dryer not heating

[toey]

The dryer runs, but has no heat.

Base on this diagram http://www.appliancepartspros.com/partsearch/model.aspx?model_id=46282&diagram_id=28471664#d28471664, I did continuity check on the timer, thermal fuse (heater), cycling th'st, hi-limit th'st, and heater.  They seem to be Ok.
I also used a screwdriver voltage tester to test each parts above while the dryer was running, and there is electric came in to them.

What else can I do to figure out what part is broken?

Thanks

Model MDE3050AGW

[On-Time Applianc]

Some times continuity checks will fool you. You must use check voltage at each of the parts you described.
On-Time Appliance

[JWWebster]

Checking a component with a light just tells ya power is going to the component. It does not tell you it is going through it though. To do the test correctly with that light you would need to remove a wire from a live component and get the bulb to burn from that live wire to the other side of the component and that would be dangerous as hell. Bypassing each component ain't the answer either ESPECIALLY if you are dealing with anythang that has electronic controls. It is best to check continuity on each component with the dryer unplugged and a wire removed from the component to prevent a false read.

[toey]

Some times continuity checks will fool you. You must use check voltage at each of the parts you described.
On-Time Appliance

The screwdriver voltage tester that I used has a voltage meter on it, and it showed that there was 220 v. going in to each part.

[toey]

Checking a component with a light just tells ya power is going to the component. It does not tell you it is going through it though. To do the test correctly with that light you would need to remove a wire from a live component and get the bulb to burn from that live wire to the other side of the component and that would be dangerous as hell. Bypassing each component ain't the answer either ESPECIALLY if you are dealing with anythang that has electronic controls. It is best to check continuity on each component with the dryer unplugged and a wire removed from the component to prevent a false read.

I did continuity check on each component as you suggested, but each component pass the test... :-(

[JWWebster]

If all the components check good and the power is there then the timer is probably bad. To test it remove the heavy red wire on the timer marked RH or whichever wire you determine to be coming from the heater element to the timer. Using a meter check for continuity between that terminal and any other terminal on the timer. Turn the timer around and test in several positions on the dial. If you cannot get a reading then the timer is bad,
Click on pic to enlarge:

[toey]

I checked the timer, and it was good.  So I did some voltage metering and found that there was 220 v. electric going in to the heater but there was no Neutral going in to the heater.
After looking at the schematic diagram, I found that there is some sort of a contact point at the motor.  I looked at the motor and found the part in the attached image.  I took it out and found a lot of dust in the part, so I cleaned it up and the heat came back... :-)

[JWWebster]

That is your cent switch. It is a safety feature which does not allow heat until the motor is going. Very rarely do these go under but I have replaced a few of these. I do not think these switches are sold separately any more. Congrats on finding that!