Fan not working properly, ramps up at ~42º else stays idle

Fan seems to be completely idle most of the time but every 3-4mins or so the temp reaches ~42º and the fan suddenly kicks in and revs up til temp drops. Rinse, repeat. Very annoying!

Fan should just stay running continuously instead of ramp up aggresively when a temp is reached.

How to fix? Any way to control / set the fan speed manually to perhaps 50% my guess is that would be enough to keep it below 42º

This question is posted in two other locations and we’re already in communication.