Fan coming on randomly

I have an amana heater/ac. Recently we have noticed that, with it turned off, the fan will come on for 15 seconds or so and then stop. It does this a few times a day normally.

Just wondering if this is normal or not and why it is coming on.

Thanks.

I am not sure but I think your heater/ ac have the sensor problem. Check the sensor.

The problem is in heater.