Systemd unit file

[isdn]

I would suggest the following systemd unit file to manage service.

The unit file (/lib/systemd/system/fancontrol.service):

[Unit]
Description=Fan control service
After=syslog.target multi-user.target

[Service]
Type=idle
ExecStart=/usr/local/bin/fancontrol.py &

[Install]
WantedBy=multi-user.target

It should be owned by root and have the 644 mode.

Then:

sudo systemctl daemon-reload
sudo systemctl enable fancontrol.service
sudo systemctl start fancontrol.service