no heat from awz121 whirlpool dryer?

All seems to be working fine, but suddenly no heat coming from the dryer.

Thought it was the element at the back, as have replaced before, but ordered new one off ebay and still the same.

Thought I might have been sold a duff one, but they seem ok and willing to replace, however have heard there is a second thermostat inside, though don't know if this is right as thought they were built into the element. If this exists and is broken, would all work the same but with no heat if the element is ok?

Grateful to anyone who can shed light on the problem.