The rear window defogger does not work: what to do? Troubleshoot problems

Most modern machines are equipped with a heating system for car stern glass. This car accessory serves to remove from its surface icing and sweating in the winter. When the heating of the rear window does not work, the visibility is significantly reduced. The driver is not able to correctly assess the situation on the road behind his car. Timely maintenance and repair of this system directly affect the safe movement. Often the breakdown of this car device is detected with the onset of cold weather, just at the wrong time.

The rear window does not work, what should I do? This question will help motorists answer this review. Here are the most frequent breakdowns of this device and how to eliminate them.

Device

Virtually all the systems of the stern window heater are identical and do not have any special differences between themselves. Both domestic and imported cars are equipped with one type of construction. Its device provides for applying to the inner side of the glass of the electricity carried by the thread, which heats up, which means that the window is heated. At the same time, melting of the ice cover and snow melts from the outside. With the internal drying of the surface from fogging occurs.

The entire system consists of several elements that ensure a normal and safe operation of the heater:

• Heating wires (their number may vary depending on the model of the device);
• Electric wires supplying current to the work area;
• Device safety relay;
• A power button equipped with an alarm LED;
• fuse.

The failure of one of the constituent elements of the heating device or a break in its electrical circuit can serve as an impetus to the question of why the heating of the rear window does not work.

Possible malfunctions and ways of their elimination

Check all the details and components of the heating device with your own hands, having little experience in repairing vehicles. Below we will consider them in more detail.

System Fuse

First of all, if the heating is faulty, you should pay attention to the safety element, as a burnout of this causes the device to not work. In different brands of cars, it can be located in different places. Therefore, to properly determine its location, it is advisable to use the service book of the vehicle. After determining the location of the fuse, it must be removed and checked for suitability. If it is blown, it must be replaced with a new one, as this may be the main reason that the rear window defogger does not work. A typical malfunction can also occur due to a breakdown of the system relay. As a rule, it is recommended that a new part be fitted to the vehicle after encountering a breakdown.

Malfunctions of electroconducting

After installing a new fuse element, you should check the operation of the heater, when the situation has not changed, you need to diagnose the power supply lines. There is a high probability that they can break, break off at the fastening or burn out, and as a result, the currents will not flow to the heating strips. Check the condition of the wires as follows: Initially, switch the heating button to the "on", then with a tester check the presence of voltage on both terminals of connecting the wires to the heating tape. Most often they are on the sides of the glass or in its lower part. If there is no voltage on the wires, then perhaps this is the reason that the rear window heater does not work. What to do in this case? To trace the entire route of the wiring, then there is a cliff. Strip the contacts of the connecting sections and terminals, as they can simply oxidize and not pass the voltage during prolonged operation. If you track the wiring path and detect damage at home is not possible, you need to resort to the help of an auto electrician.

Threads

Damage to warming strips is another option for why the rear window defogging does not work. What to do in this situation and how to identify the damaged site? First, let's look at how the workflow in threads works. Voltage goes to the entire heating element and is evenly distributed across all tapes that have a parallel connection according to the base. Thus, electrical tapes act as conductors of currents and, due to a certain percentage of the resistance, they heat up to insignificant temperature, but at the same time it is enough for warming up. If one or several tapes are damaged, the current is cut off from them, and, accordingly, the heating of these sections is impossible.

Controls

What should I do if the rear window does not work, and the diagnostics showed that all the elements of the system are working? Perhaps the reason for this may be the power button. At the moment of heating on the button, the light indicator lights up, which indicates the operation of the system. So, the toggle switch is in the "on" position, the warning light is on, and no warm-up occurs. This indicates that the working contacts of the toggle switch are burned out or worn out over time, so there is no supply of energy for heating. With this breakdown, you need to replace the button, since it is almost impossible to repair the damaged one.

Restoration of heating strips

So, does not work the heating of the rear window, what to do and where to start repairing. The first thing to do is to get a quality repair kit for the restoration of electrical threads. You can buy it in any car dealer or at the car market at a very reasonable price, but not cheaper than three hundred rubles. Too cheap sets have low quality materials and simply can not solve problems. The repair kit includes glue or varnish with high conductivity currents, a brush for its application, as well as a sticky tape to mark the boundaries of the application of the conductor. Buying a repair kit, you need to determine the color of the conductive means, so that it does not differ from the color of the tapes on the car.

Technological process of repair in stages

First, we determine the place of rupture of the chain on the filaments. Often, it is not difficult to determine these, they are visible to the naked eye. Usually, this is mechanical damage in the form of scratches, rubbing and large torn pieces.

Then we study the instruction on the use of the repair kit: the methods of applying the conductive means and the time until it dries completely. The next step should be to prepare the surface of the damaged area for recovery. To do this, just wipe it with a rag soaked in alcohol to remove dirt from it and degrease it.

After that, stick strips of adhesive tape on both sides of the thread in the rupture area. Glue the adhesive tape so that the width between the bands is equal to the heating thread. Next, apply the brush tool to the place of rupture in several layers, the number of which is indicated in the instruction. We give the varnish to dry - often the drying time of the varnish is equal to one day. When the varnish is completely dry, you can peel off the adhesive tape and check the heating function. If, due to damaged threads, the heating of the rear window of the VAZ does not work, then the repair process can be carried out in the same way as above.

Imported cars

On the machines of imported production, in addition to the standard heating of the rear window, such a device is completed and rear-view mirrors. The principle of the operation of such equipment is the following. Including heating the stern glass, the mirrors are heated in parallel. Therefore, if the rear window and mirrors do not work simultaneously on the car, the reason is likely to be in the faulty state of the relay or fuse, and it is not worth while to sin on electric wires. It is worth noting that the heating system can have several fuses in the circuit, so it is important which ones are responsible for the glass. For example, if the rear window heater does not work on the Chevrolet Lachetti car, it is important to pay attention to the fuses under the labeling F6, Ef7 and the safety element of the relay K10. It is also necessary to take seriously the electronic control card of the system, which, in turn, very quickly fails due to the rupture of tracks and the soldering of contacts.