Where is the sensor that turns on the rad fan on a signum?

In a Vauxhall Signum, the sensor that activates the radiator fan is typically located on the engine's coolant temperature sensor or in the radiator itself. This sensor monitors the coolant temperature and signals the fan to turn on when the temperature exceeds a certain threshold. Ensure to check the vehicle's service manual for the exact location, as it can vary based on the engine type and model year.