There are two heaters, one for the washer & one for the dryer. The dryer heater is mounted in an aluminum box directly under the lid. The water heater is mounted in the bottom of the drum. Once the lid is off you will see the heater box with two thermostats on the left + NTC probe at the front. The fan assembly is towards the rear of the box. The most common problem is that the resettable thermostat trips because of a clogged heater box, fan housing, defective fan, blocked condenser etc. There are other causes of dryer no-heat, including bad contacts, broken wires, NTC failure, or a faulty pcb. Washer/dryers were a great idea on paper, in reality they are all plagued by problems with the dryer sooner or later. If you feel further investigation is beyond your DIY skills perhaps you should call qualified assistance. Remember to pull the plug before taking off the lid....