Chosen Solution
I just upgraded the RAM in my late 2018 Mac mini, and now the fan seems to run all the time. Prior to the upgrade it was rare that I heard it. It might ramp up but then would go back down. Now it’s always audible & running. Went from 8GB to 32GB - So far everything seems to be functioning as normal.
I had this on a earlier generation Mini and it was because on of the cables for the sensor’s were loose. Not sure if this is the same issue on the 2018 model.
