Hi ,It will be the 185 degree thermal trip located on top of the heater box. it blows and dosent reset as it is a one shot device . Google it there are lots of suppliers.
regards
alistair taylor, January 2008
I had this problem....it needed a new thermostat and relay. These are found on top of the section with the metal jacket on it, and they are the two little black switches on top of that.
vicky, October 2007
I fixed my miele dryer by resetting the switch.that should be the concept for all the dryer open the top of your dryer and check any switch which you can press should be small switch just press that it might work it worked on my dryer.Good Luck.