Provided you are referring to "Fan Control" from Lobotomo, they provide removal instructions:
Uninstall Instructions
Please follow these instructions to uninstall FanControl permanently:
- Remove the following files and folders (both on your start disk):
/Library/StartupItems/FanControlDaemon /Library/PreferencePanes/Fan Control.prefPane
(You will be prompted for the Administrator's password when deleting these items.)
- Reboot
- Reset the System Management Controller (SMC). Please follow these links for instructions: Portables, Mac Mini, Mac Pro
The above is provided on their site here:
http://www.lobotomo.com/products/FanControl/