I am in a 15 year-old home; the utility 'room' is a closet off a hall, with room for a washer and dryer only. There is one ceiling light and an extractor fan next to the light. There is only one wall switch. As of 2 days ago, the fan runs constantly - 24 hours; turning the light switch on and off does not turn off the fan. There is no burning odor - it simply will not turn off. I turned the light control off at the breaker box, and on again - did not correct the problem. Ran the cold water, then the hot water, then turned them off - no help in stopping the fan running! Am I correct in assuming that if there is only one switch, that the switch controls both light and fan? Why will the fan not stop running, and what can I do about it? I would appreciate the help please. Thank you.

There must be one circuit breaker that shuts off the fan. Try them all, one at a time.

Then you can have the fan looked at, as there is something causing the fan to run.

What normally controls the fan? The light switch for the utility closet?

Thank you for responding. I tried shutting off the circuit breaker, but when I turned it back on again, the fan came back on! I assume the light switch controls the fan too. Not paid attention to it until fan started running all the time. There is no other switch in there, so it must be controlled by the light switch.

OK, there may be an issue at the switch, either some sort of short causing the switch to be jumped out, or a defective switch.

Since you use the word "extractor", I will guess that your not in North America, UK perhaps.

USA uses 120 volts, UK uses 220-240 volts, so, if your not capable with working with these voltages, you really should call in a pro to check out the switch.

This fan not working by the switch can be an indication of a more serious hidden issue.

I just turned off the power at every breaker switch. Everything off, including the fan in the utility closet. Then turned them on one at a time, as you initially suggested. Guess what? The fan in the utility closet is on a separate breaker from the light in the utility closet. The fan is on the same breaker as the bathroom next to the utility closet. That breaker handles the bathroom light, bathroom fan, and the utility closet fan! The light switch for the utility closet is separate. So I have no idea what makes the utility closet fan turn on and off - there is no switch for it! When I throw the breaker back on, the fan in the utility comes on again. There is no control to use to turn it off. I have not noticed it even working until two days agao, when it 'came on' and won't turn off!

I know it's pretty far out but could the fan be on a humidistat, a photo cell or a door switch?