indesit washer/dryer w12 dryer heater stays on?

my indesit w12 washer dryer stopped working and I could smell something was getting very hot. The program switch keeps turning with the red light flasing. After a little research I found fault codes and reset posted. The light flashes 13 times which is the dryer fan fault so I removed the unit cleaned the interrior and tested the fan which works perfectly. Replaced the unit checked high pressure switch also found to be fine. The dyer heater & fan appear to be stuck on which I think may be the relay or another component on the pcb. Can anyone please confirm or know where the board can be checked out at a reasonable cost !