cat /sys/class/thermal/cooling_device0/type
should give rpi-poe-fan
sudo vi /etc/udev/rules.d/50-rpi-fan.rules
SUBSYSTEM=="thermal"
KERNEL=="thermal_zone3"
# If the temp hits 81C, highest RPM
ATTR{trip_point_0_temp}="82000"
ATTR{trip_point_0_hyst}="3000"
#
# If the temp hits 80C, higher RPM
ATTR{trip_point_1_temp}="81000"
ATTR{trip_point_1_hyst}="2000"
#
# If the temp hits 70C, higher RPM
ATTR{trip_point_2_temp}="71000"
ATTR{trip_point_2_hyst}="3000"
#
# If the temp hits 60C, turn on the fan
ATTR{trip_point_3_temp}="61000"
ATTR{trip_point_3_hyst}="5000"
#
# Fan is off otherwise
sudo udevadm control --reload-rules && udevadm trigger