You can check the heating element using a multimeter on the Ohm settings.
Disconnect the two wires and test the heater plus and minus - It should show a value between 35 to 50 ohms. If it shows 0ohms it is broken.
Keep on measuring it and knock it with your hand or with a hammer lightly in it is in a tube or something. If it the ohms jump around then it means it is broken has micro short circuits.
Where and how to get to it we cannot really help here. You need to check you manual. There are allot of websites that have the manual to download. I am sure the manufacturers website will also have one.
I strongly doubt there is any security feature- expect for short circuits. So if it has problems heating.. then most of the time the heating element is broken the other time it is faulty heat switch.