Here are your parts
You should look in the Matching Model Numbers section for the correct series number.
Parts for AOES3030WW - AppliancePartsPros.comSee the attachment for the tech sheet
The first thing I would check is the power.
Try flipping the breaker off/on slowly a couple times. Sometimes you can loose half the line without actually tripping the breaker.
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.
Do this with the heater off and on.
[COLOR="Red"]Be careful as 240 volts is lethal !!![/COLOR]
Yes there looks like there is a hi-limit thermostat. I think it is item 38 in section 02 but am not 100% sure so you will have to trace the wires to confirm that it is the correct part to check.
I am assuming that the unit stays in preheat and never comes ready.