Have the motor checked and replaced if no runnig the oven will not heat as it is a safty measure
on moter the fan blade could have been loose, the motor bearings could be worn out or the fan motor gone kaput

This tutorial will show you how to check your Zanussi element and how to replace your Zanussi cooker element.
Here are the 3 main faults to look for in your oven or cooker that is not heating

1. Your oven will not work until the clock/timer has been re-set after replacing an oven element or tripping the electrical supply. Consult your Zanussi manual.
2. If you're Oven is not getting hot or heating up it could be a faulty element, if the fan in the oven is running and the thermostat light is on, this will lead us to believe that the element has gone faulty. With grills the thermostat light should come on there should be heat, if not then this could be the grill element or the thermostat.
3. When you turn the oven on, the household electrical supply trips on the Rcd (this is the earth trip in the fuse board sometimes called the breaker tripping) your fan oven element has gone to earth and needs replacing.