Hi i got called to a job yesterday on a tumble dryer, it was getting hot and cutting out so i took the heater off to check the stats, there were 3 there, iv’e only ever seen two, the control stat and the overheat stat, could someone tell me what the 3rd one is, it sits between the other two, i tested all 3 but couldn’t get a reading on the middle one, any advice would be good