Function:

• It’s an electrical switch that acts based on the temperature of the coolant in the radiator
• It activates the electric fan forcing air entering through the radiator, this causes the diminution of the temperature of the cooling liquid until the automatic disconnection of the ventilator
• It can be opened normal or closed normal depending on the electrical circuit of the vehicle

Functioning principle

The thermocontact uses a bimetallic disc made up of two metals with different thermal expansions. The deformation of the disc to certain temperatures is used to move an axis that acts on the silver contacts, obtaining this way the connection and disconnection. 

In the case of thermocontacts with 2 speeds are used two bimetallic discs that are used in vehicles where the need to running of the electrical fan has two positions, one of idling and another one of full swing.