The fans are always running on Tiertime machines. The stepper motors on the extruders get hot, and so they keep them running at all times along with the heatsink paired to it. The fans Tiertime use are very good and last a very long time. My UP Plus 2 still has its factory stock fan on it, no issues whatsoever, so don’t worry about fan wear.
If it’s an issue from a part/layer cooling point of view, close off the duct and put tape across if need be. I would advise leaving the fan alone, not that we have any software control over it.