I do not know if they monitor the thermistor readings and if they get out too far from each other the board shuts down.
Looks like they may us the hi-limit thermostat to power the motor.
Try an air only cycle.
Does it still shut down?
Is there heat? If there is heat then you probably have a grounded element
re: it has broken or sagged and is touching the case/frame in such a way that it is overheating the hi-limit.
The way to check for a grounded element is to disconnect and measure across it, they are usually 10 to 30 ohms. Then measure from each heater connection to the frame or neutral, both should be infinite ohms. If using the frame be sure to find a spot with bare metal.
This is for a 3 wire hook up with a 4 wire hook up you must check to the frame.