Quite possible that one of the thermal cut-outs has burnt out. Quite a common problem, for which you need to replace teh heater element (as they are an integral part). You might also want to check the connections for the heater element.
Dave
November 2005
I hope you didn't touch one of the thermal limit switches. There are two located close to the elements, IF you pressed in the cap it will permanently be tripped and you will have to buy new thermoswitches (they come as a pair) one is for the normal temperature regulation and the other is a safety cut-off for when the 1st one fails
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Try fixfault.com to fix tumble dryers.