Vauxhall Corsa C - Fan constantly on - Min

My fan is constantly on at the moment. I can be running the car for a few seconds and switch the engine off and my fan is still on. Ive checked my radiator and its water level is fine. Anyone have any ideas?

Vauxhall Corsa C - Fan constantly on - Collos25

The temp sensor is faulty or the ecu is sending the wrong signal .