When the electric fan fails when driving outside the city, it's not scary. The flow of oncoming air is sufficient for cooling. But if it happens in a traffic jam, then what to do? In fact, the control circuit consists of several parts that can be replaced on the fly.
An electric fan installed on the radiator of VAZ cars is designed for forced blowing of the coolant in the system. At high speed, the oncoming air flow copes with this function perfectly, but when driving through traffic jams, when the heat comes from the surface of the asphalt, neighboring cars, the cooling is much worse. But the electric fan is able to provide quick cooling of the liquid to the operating temperature.
Antifreeze and antifreeze in a sealed cooling system have an increased boiling point, but this does not help when driving through traffic jams. But what to do if the electric fan fails and the coolant starts to boil away? The main thing is not to panic and try to make the right decision for a particular situation. Try to make a diagnosis as accurately as possible, then it will be easier to get out of this situation.
Electric fan switching circuit
The electric fan is switched on using a temperature sensor installed in the radiator. Some vehicles have an additional sensor in the engine block that turns on the blower at low speed. This is done by feeding the motor winding through a resistor. The control scheme may also differ from vehicle to vehicle. The simplest circuit consists of the fan itself, a fuse, a temperature sensor and connecting wires.
The fuse is selected based on the fan power. And the sensor acts as a power switch. As a rule, the sensor is installed in a gap in the negative wire. For example, on the VAZ 2109, starting in 1996, only such a switching scheme was used. The designers made a small oversight, since the wire that goes from the sensor to ground is very long. During operation, it can be damaged, which is why the whole circuit will stop working.
The temperature sensor can also fail, this is not uncommon. To replace it, it is necessary to drain the coolant from the radiator, since the sensor is located at the bottom of it on most cars. The electric fan control circuit, which uses an electromagnetic relay, is a little more complicated, but due to this relay itself, it has less reliability. An extra part that can fail at the wrong time. But on the other hand, there are small currents on the sensor, all the high current passes through the relay contacts.
What if the fan fails?
The simplest case is a blown fuse. To restore it, you just need to find its location according to the scheme and replace it with a similar one. You can not put a fuse, the operating current of which is much higher than it should be. The same applies to bugs. But if the temperature sensor fails, you will have to act with an eye on the current situation. If you are driving on the highway, then the flow of oncoming air should be sufficient for cooling.
But if you are driving around the city, then the best way out will be to close the sensor leads. The same should be done if a relay is installed in the control circuit, and it burned out. But if the damage is somewhere in the wiring, then the best way out of the situation is to connect the fan to the battery terminals. Just remember to turn it off before turning off the engine.
