The electric motor is switched on by sensor 2 (pic. 131) and auxiliary relay 5 installed in the mounting block. The sensor is wrapped in the right radiator tank. When the coolant temperature (and sensor) will exceed (99±3) °С, the sensor contacts are closed and through them voltage is applied to the coil of relay 5. The relay is activated and turns on the fan motor. Sensor contacts open at temperature (94±3) °C. In this case, the relay winding is de-energized and it turns off the electric motor.
Pic. 131. Scheme of switching on the electric motor of the fan of the engine cooling system:
1 - electric motor; 2 - sensor for turning on the electric motor; 3 - mounting block; 4 - ignition switch; 5 - relay for turning on the fan motor.
If the electric motor does not turn on when the coolant temperature is above 102°C, it is necessary to check the wires and their connections in the electric motor switching system, check the operation of the sensor, remove the relay cover and clean its contacts.