The part(s) or condition(s) listed below for the symptom Oven fan won't turn off are ordered from most likely to least likely to occur. Check or test each item, starting with the items at the top of the page.
The oven control board has relays that regulate power to the bake, broil and fan circuits according to the user settings and sensor input. If one of these relays shorts out, the control board may send continuous voltage to the oven fan. However, this is rarely the case. Before replacing the control board, first check the oven thermostats. If an oven thermostat fails, it may cause the oven fan to run continuously.