common problem on the whirlpool tumble dryers. Remover the lid, then the rear panel. u will need a T15 star drive screwdriver. you will then see the connections for the element and thermostats, these usually burn out, it will be obvious as to whats wrong. usually a connection to the thermostats is completely burnt. you need to replaced the stats and replace the spade connectors, but they need to be heat resistant connections as it will take a lot of current, and the heater is right next to it.
Lucy, white goods engineer, January 2012
