Here is a link. Look at #8
http://www.applianceaid.com/diagrams.html

This is probably close to your unit.
Least confusing way I could think of explaining it

TIMED DRY
Circuit Path:Neutral (R), DOOR switch (D/D1), Timer Contacts WB/TM, TIMER MOTOR, L1
So the timer motor gets 120 volts all the time

AUTO DRY
Circuit Path: L2, Motor's centrifugal switch 2M/1M, HEATER, RESISTOR, Timer Contacts OR/TM, TIMER MOTOR, L2
Right side of the heater with the heater on is actually L1, re: timer contacts R and the 2 thermostats are closed. So the timer motor gets no voltage.
Now if one of the thermostats opens the left side of the Heater becomes L2 and current flows through the Auto path. The resistor is there to reduce the 220 volts to 120 volts so that the timer motor gets the correct voltage across it. Therefore your time only advances when the heater is off.

I have no idea what the interior temperatures should be.
Your way of testing the thermostats is valid.
Be very careful that you do not overheat and cause damage to the dryer or worse yet a fire.
Usually all I do is heat up the face with a soldering gun if it opens normally it is OK. Usually the contacts weld together so the cannot open.
Or you could remove them from the machine and heat the face up on a stove element or in the stove.
Note it makes no difference if you are in timed dry or auto.

Hope this helps