Make sure you
cd fanshim-python
cd examples
sudo systemctl stop pimoroni-fanshim.service
Then run the install again with the --noled option.
The fan will just run continuously with no software installed, it will still cool your Pi.
Another option instead of the service is to add the following to your config.txt file.
dtoverlay=gpio-fan,gpiopin=18,temp=55000
It will turn on at 55c and off again at 45c. You can change the 5500 to what ever temp you want.
If you also add this line, pressing the fan shim button will have the Pi do a proper shutdown.
dtoverlay=gpio-shutdown,gpio_pin=17,active_low=1,gpio_pull=up