Dx302 not heating in fan dry stage ?

Hi, our dishwasher was not heating the water during any stages so we followed the instructions and re soldered the joints. Water is now heating well but when it comes to the dry cycle you can hear the fan working but it is not heating and when the dishwasher has finished the cycle the fan keeps going. This is the forth time we have had to solder the joints so will never buy another dishlex!
Thanks for your help in advance :)