The current in the car is supplied from the positive through the ignition switch, as well as through the fuses. Then the voltage passes to the heater switch and is connected to the battery minus with the car body. One of the wires of the glass heating system is also connected to the body.
When the driver presses the system enable button, voltage is applied to the relay. It works, the power contacts are closed. The current enters the heaters, passes through the heating filaments and then goes through the body to the battery.
Heating element device
The heating element has the following device. There are conductive tires on the sides of the rear window. Special threads made of high-resistance materials are attached to them. The resistance of each thread is 10 ohms.
Their number depends on the size of the glass. So, each thread is a separate element that works separately from the others. All elements are connected to each other in parallel. Such a scheme allows to provide the system with high reliability. So, if one thread breaks, all the others will work.
Typical malfunctions
Before repairing heating filaments rear window with your own hands, you need to find out the malfunctions. Depending on what kind of malfunction manifests itself outwardly, it is possible to diagnose the operation of the system even without a multimeter.
It should be noted that the glass heating can only be started when the ignition is switched on. On some car models, you can turn on the glass heating only when the engine is running. This is done in order to reduce the load on the battery. The system for full operation requires from 10 to 25 A of current.
Heating does not turn on
So, if the system does not turn on from the corresponding button, the corresponding fuse may have failed. The button may also be broken. If the operation indicators are lit, but the glass does not fog up, repairing the rear window heating filaments should begin with checking the connectors and relays. In this case, according to the electrical circuits, they find where the parts are installed and change them.
Slow sweat
Sometimes it is possible to observe cases when a significant amount of time passes between pressing the button and turning on the heating system to demist the glass. If there is low air temperature or frost outside, then the cause of this problem may be in poor contacts on one of the connectors. The resistance on the contact increases, the current becomes lower, the power drops.
To check this fault, you must use a multimeter. Change the voltage at the terminals of the heating system and the battery. These voltages should not differ.
There are streaks on the glass
This is the most common error. The problem is related to the breakage of the threads that are applied to the glass. This malfunction can be diagnosed by the stripes on the glass after the system is turned on.
The threads installed on the rear window are of low strength. And if they are mechanically acted at least a little, then the rear window heating filaments will need to be repaired.
Determine the location of the break
Finding a cliff is not difficult. Near the thread, fogging or permafrost will not disappear. That is why, in order to quickly find the damaged element, the threads count and then find the damaged place. But sometimes the cliffs are so insignificant that it is very difficult to notice them. Then you should use a voltmeter.
Due to the fact that one of the tires is connected to the car body, the negative wire of the multimeter is connected to the body. Next, the positive wire with the probe touches the first and second tires. On the first, the voltage is +12 V, and on the second - 0 V. If for some reason there is no access to the tires, then measurements can be taken where the threads come out from under the seal.
If the heating is on, there is 12 V in the system, but the threads do not heat, then this indicates that all wiring to the first bus is in working order. If there is no voltage, then this indicates poor contact. It is necessary to repair the threads and contacts of the heated rear window. The relay may also fail.
If there is voltage not only on the first, but also on the second bus, then they look for bad contacts in the circuit connecting the wires of the heating system to ground.
How to find a break
The filament is a tape with a resistance of 10 ohms. In different places, the voltage will be different. At the first point, the voltage will be 12 V, at the third - 6 V, at the fifth - 0 V. If you do not know which of the threads is damaged, it is easy to find. To do this, measure the voltage in the middle of each strip. If the thread is broken, then the voltage will be either 12 V or 0. Therefore, the break is on the left or right.
Repair
There are several ways to repair this system. The most efficient and fastest way is to use a rear window defogger filament repair kit.
There are many of them, they are designed to restore the integrity of the tapes. This set has it all. It is a syringe with a special paste. Reviews characterize Permatex well. Repair of rear window heating threads with it is very easy and simple. You don't need any additional tools. Everything is in the set.
So, how to make repairs? Everything is very simple:
- Using alcohol or a solvent, we clean the area of \u200b\u200bthe glass at the point where the thread breaks.
- We take an adhesive tape in our hands and stick it on both sides of the heating element. In this case, the distance between the tape should not differ from the thickness of the heating thread.
- Using a brush or syringe, apply conductive glue or paste (depending on which kit will be used). How to apply it? The glue should cover the whole part of the thread by 10 millimeters on each side.
- Remove the tape and wait for the glue to dry. According to the instructions, the composition dries in 24 hours.
- After a day, remove excess glue. This can be done with a sharp knife - kitchen or clerical. Be careful - the knife can easily damage the surface of the heating element.
- We wipe the glass with a soft and slightly damp cloth.
- We check the functionality of the element.
You can also use another product to repair the heated rear window filaments. This is "Elecont" of domestic production. The mass is applied to the place where the thread is broken. Glue is applied so that it overlaps the whole part of the thread on each side. After curing, the electric heating system will work again.
It is believed that glue can be made by yourself (from metal shavings). But you should not do this. The finished product is much more efficient. In addition, the reliability of the technology self-manufacturing glue is not confirmed.
Conclusion
So, we found out how the heating threads are arranged and how to repair them. The complexity of the repair lies in finding a broken tape. After all, the system will work even when half of all available threads break. True, the glass in this case will fog up half.
Many drivers are interested in what to do if the heating located on the rear window does not work? This is not just a whim, but a vital necessity that allows you to always see what is happening behind.
If, when looking in the rearview mirror, the driver sees nothing but fog, then the risk of an accident increases many times over. That is why, as soon as you notice that the heating of the electric filaments of the rear window does not work, you must immediately take up its repair.
This is not a particularly complicated procedure, but in order for everything to go as it should, it is necessary to approach it as responsibly as possible. It is very important that you follow the instructions exactly.
Features of the heating system for the rear window
Heating design
Before proceeding to repair the heating of the rear window elements, which you will do yourself, you need to understand the design of this device. In reality, it is nothing complicated.
On the sides of the rear window vehicle there are two conductive bars. Between them are heating lines. Usually, high-resistance material is used to create them. The fact is that for effective operation, each thread must have a resistance in the region of 10 ohms. This is the only way to protect the glass from fogging.
The number of threads in the heating of the rear glass is different for each car. In most cases, it depends on the length of the surface. When repairing, this only affects the difficulty of detecting a break.
Important! All heating lines are connected in parallel. As a result, the breakage of one of them does not affect the operation of the others.
Connecting to the onboard network
To fix the heated rear window filaments, you will need to study the connection diagram of this device to the car electrical network. The main role here is played by the ignition switch. It is through it that voltage is supplied to the heating system.
Attention! For stable operation of the device, one output is connected to the mass of the machine.
As soon as you turn on the heater, current flows to the relay. After that, the contacts are closed, and the conclusions are connected. As a result, electricity is supplied to the heater without obstruction.
As soon as the current enters the electrical circuit of the glass heater, it begins to feed the threads, which are connected in parallel to the common system. But that's not all. The fact is that the negative contact of the battery is also brought to the mass of the car. Due to this, a constant exchange of current is carried out.
As you already understood from the material presented above, the heating of each thread of the rear seat works thanks to the ignition key. As soon as it is in the ON position, the entire system is activated.
Attention! In some vehicles, the rear window defroster is only activated when the engine is running.
Many drivers are outraged by this decision of the designers, but in reality it has its own logic. The fact is that the rear window defroster consumes a lot of electricity. Typically, this indicator varies in the range from 10 to 25 A.
To better understand how much 25 A is, let's make a visual comparison. In order to be alone headlamp could shine at least 5 A. In fact one heater is equal to 5 headlights.
What can be faults other than broken threads
To fix something, you first need to diagnose the breakdown. According to a number of signs, it is possible to find out in advance what exactly is the reason for the failure of heating the filaments. So the non-working indicator of the rear window defroster, when the button is pressed, indicates defective fuse.
An illuminated indicator and non-heating heating filaments located on the rear window indicate a malfunction in the relay. On the other hand, poor contact wiring diagram leads to too slow fogging of the glass.
We carry out heating repairs
Finding the place of the break
It is from this that you need to begin the procedure for restoring the normal operation of the heating of all rear window filaments. To begin, view all the lines visually. If nothing is visible, you can use the search methods that have been developed by other drivers who have encountered the same problem:
- If at first glance, when examining the rear window, you did not find a break in the heating lines, you should not immediately move on to more complex methods. To get started, just turn off the heat. In a place where the glass is not heated, a characteristic strip will appear.
- Take a voltmeter, turn on the heating rear seats. Install one probe on the ground of the machine, wrap the second with foil. At the same time, slowly move along each line until you reach the middle. The standard voltage is 5 V. If it drops below, then you have found the place of the break. A jump to 12 V also indicates a break.
- There is another option for using a voltmeter. To do this, connect the plus to the terminal to the corresponding heating contact. The second probe must be moved slowly along the line. Moreover, this must be done from the side where the negative terminal is located. A drop in voltage means that you have found a break.
- Ohmmeter. An ordinary pointer device will work best. When you turn on the device, you must select the mega mode. Connect the probes to the heating terminals on the rear window. As a connecting element, ordinary cotton wool soaked in distilled water is suitable. Run along the line. The reaction of the arrow will mean that you have found the place of the cliff.
As soon as the place of the break in the heating threads of the glass behind is found, you can proceed to a full repair.
We repair heating
There are many methods for repairing threads that are responsible for heating the glass of a car in the back. To for example, you can take a regular repair kit for the corresponding part. The advantage of this option is that you do not have to look for additional spare parts and tools. Everything will be in one package.
Attention! Before you start soldering, clean and degrease the wires of the heating system.
Some of the best kits for repairing damaged rear window heating lines are made by Permatex and Quick Grid. All of them have similar accessories.
The repair kit allows you to restore about 10 centimeters of a damaged thread. Usually the set already has ready-made lines. All you need is to install them correctly.
The algorithm for repairing rear window thermal lines using a repair kit is very simple. You need to replace the damaged thread and apply the compound to where the damage was.
Important! The procedure must be repeated two or three times for it to have an effect.
At the end of the work, remove the template. Heating can not be turned on for at least a day after you have done everything. Otherwise, all the work will be useless and you will have to redo it again.
The second do-it-yourself method for repairing rear window heating lines is to use conductive paste. Just apply it to the place where the threads were broken. Please wait 24 hours. After that, all functions of the thermal lines will be restored.
Advice! If you are pressed for time and need to go somewhere urgently, use a regular hair dryer to speed up the process.
Folk repair methods
Of course, using a repair kit and thermal paste has its advantages. They are easy to operate, and the result of repairing heating filaments made of a special material for the rear window with these tools is always at a high level. However, they still need to be purchased. And that takes time and money. In some cases, both with the first and with the second, some difficulties are possible.
It is not surprising that domestic and foreign motorists have come up with a whole set of various methods that can help restore broken lines in the shortest possible time using the tools at hand.
In order to bring to life the first folk method of repairing heated rear window filaments, you will need paint and shavings. To mine shavings need a copper-brass bar and a file. The color of the paint doesn't really matter. However, it is preferable that it matches the threads.
Shavings and paint are mixed in a ratio of one to one. As a result, you should get some kind of dough from these two elements. In order to make a stencil, regular tape will do.
After the stencil is applied to the surface, turn on the heating of the filaments with a resistance of 10 ohms for the rear window. Only then apply the restorative mixture. As soon as the dough hits the damaged area, a specific hiss will be heard.
The main advantage of the paint and shavings technique when repairing a heated rear window is that you don't have to wait. As soon as an easily recognizable hiss is heard, you can immediately go to the track without fear that the rear window will fog up.
The second popular method for repairing a heating system installed on the rear window has some differences from the first. The mixture also uses shavings, but the paint is replaced with glue. Ideal for BF-2. Its restorative qualities will be more than enough to restore damaged threads.
Important! To ensure a more reliable contact, thin wires can be used.
The third folk method of repairing the heating filaments attached to the rear glass is the usual soldering. To do this, you will need flux and zinc chloride. Of course, you can't do without solder either. The vein that you will use during work should be silver. Alternatively, copper can be used.
As you can see, folk methods make it possible to restore even the most serious breaks in the heating lines on the rear window of a car at minimal cost. Unfortunately, unlike ready-made pasta, you will have to make the composition yourself. And this takes time and effort.
Results
Heated high-resistance rear window filaments can be repaired with your own hands. To do this, you do not even need to buy a repair kit or paste. Enough improvised means in the form of a bar and paint.
In cold weather or just in rainy weather, when you turn on the heated rear window, you can find that it simply does not work - either completely, fogging does not go away, or one or more threads do not heat up. This reduces the view from the rear window – which can have a negative impact on driving safety! Need to be restored. BUT how, what to do? It turns out that everything is quite simple, we read ...
Actually, the reason has long been known to everyone, on our VAZs, these threads were constantly “burning”, and they rode with 1 - 2 - 3 threads that did not warm up, terribly inconvenient! But now it turns out that for a long time there are tools and repair kits that allow you to restore the whole thing, and quite effectively.
How does the heated rear window work?
Everything is just wires with a voltage of 12 volts to the rear window. On the surface on the sides there are special tracks into which these wires are embedded. The tracks go vertically up, so to speak - the "main bus", there are two of them on the right and left, at the extreme points.
And now they come from them, thin (2 - 3 mm), horizontal strips that heat up the glass itself, clearing it from fogging or snow in winter. They are the main working element of the whole structure.
Usually there are several dozen of them, about 20 - 40 in the working area, it all depends on the class of the car and the size of its rear window.
Of course, any electrical device is controlled by a fuse, which is designed for a certain voltage and amperage.
Doesn't work what is the reason?
Actually, there are only two main reasons, and both of them lie in the power system:
- Fuse. YES, it can actually burn out. This happens due to various reasons, maybe it’s not a big short circuit and that’s it. Thus, the heating will not work for you completely. Need to find . This is the first and mandatory step.
- If it is intact, then we need to check the voltage on the wires that fit the main "tires" (side wide strips). As a rule, they have ordinary metal contacts. We just take a multimeter and measure it, if there is voltage and it is about 12 volts, then the power is coming here, everything is in order.
- The thin lines themselves. To be honest, all of them cannot burn out at once. As a rule, it burns out from one to three, well, a maximum of four “threads”. Therefore, if you have part of the window moving away (from fogging or ice), but not part. It is necessary to look at non-working threads.
- Examine this thin strip and you will see the place of the break. This will be the burnt part, there may be a little black around it (although the thread is initially brown). Also, the thread will, as it were, open, and this place must be connected in order to restore working capacity.
From myself I want to add that the fuse rarely burns, basically it is a break in the "threads" of glass, it is they who need to be restored.
Do-it-yourself heating repair
I remember a long time ago when it was almost impossible! Now what technology has come to - you can buy a rear window repair kit, just to restore these narrow strips. I suspect that there is some kind of metallized composition, or paint - but it is called conductive glue.
Such glue withstands temperatures from - 60 to + 100 degrees Celsius. That is what we need to buy. The only thing I want to tell you - do not take the cheapest composition, now in my opinion it is about 150 - 200 rubles, take a little more expensive about 300 - 400 rubles, such compositions work much longer.
Now the actual instructions for recovery:
- To begin with, you need a little, I repeat a little - to clean the edges of the strip in the places of the cliff. It is necessary to remove soot and other deposits that form on the glass. For this, sandpaper "null" is ideal, just a couple of movements and you're done.
- We wipe with alcohol, remove all plaque.
- Now we take the adhesive tape, and paste the strips on the sides, in its thickness. The adhesive tape should not cover the strip, but it should not move away from it for a long distance exactly along the width of the thread, so that there are no gaps.
- Next, we take our composition, “conductive glue”. He either has a syringe or a special brush. We begin to paint over the place that we have prepared. How many layers to apply will be written in the instructions. So it is worth noting that you need to go to the working sections of the strip 1 centimeter to the right and left.
- Now we need to dry the composition. Take off the tape and wait. Usually about 24 hours is enough. BUT NOT EARLIER! After that we turn on and check the performance, everything should work.
That's all, this is not a complicated instruction. Now we are watching the video version.
At any time of the year, the driver needs a properly working car. And sometimes some details are considered not so important, but according to the law of meanness, they will be needed in difficult times. One of the troubles that can happen to a driver on the road is damage to the rear window heating system. Both in winter during the period of cold weather, and in summer in rainy weather, this function of the car must be performed in full. Otherwise, moisture will get into the cabin, and visibility will be reduced to the limit, as a result, the driver is forced to repair the rear window heater of the car.
Heating system and functions
The heater is powered by electricity. It is known that on windshield warm air currents affect, special heating elements are needed for the rear. It's no secret to anyone that inner side rear window is equipped with metal tracks that have high resistance to electric current. When current flows through the ribbons, heat is released and, accordingly, heating occurs. The result is obvious: clear, dry, heated glass.
The main function of this structural element is to combat icing, moisture and fogging. As soon as the system starts to work, after a short period of time the glass is clean and transparent. In addition, this function allows you not to overdry the air in the car.
Damage to the heating system
As a rule, the driver notices damage in this part of the car only when the rear window is constantly sweating and does not get rid of ice. After turning on the heater, ideally, after a couple of minutes, it should be transparent and clean, but if this does not happen, then damage or malfunction has occurred. Among the damage to the system should be highlighted:
- Slow glass fogging. If visibility does not improve after a few minutes of heating operation, there is a malfunction. The reason may be hidden in the loose contact of the circuit connector.
- The inability of the heater to work when it is turned on. In this case, after pressing the indicator is not lit. This may be due to a faulty key or a blown fuse.
- The presence of horizontal lines of fogging on the glass. As a rule, such a malfunction can occur due to a break in the heating filaments that are applied to the glass surface.
Slow glass fogging
Whatever happens, the main thing is to make the correct repair of the rear window heating with your own hands or with the help of a specialist.
Fault detection and repair
It is believed that it is quite simple to determine the damage in the heating system, and every driver will cope with the task. Before starting work, it is recommended to count the threads applied to the glass, so that later it will be easier to remember which one is damaged. There are cases when the gap cannot be seen: it is so small that one of the instruments should be used. It can be a voltmeter or a multimeter. In any case, in order to repair the rear window heating filaments, you need to carefully examine the surface and identify damage.
There are several effective ways to troubleshoot:
- Method of visual diagnostics - in damaged areas, when the heating is on, the glass does not warm up and remains misted.
- Using a voltmeter - with the heater turned on, one probe should be placed on the "mass" of the machine, and the second, wrapped in foil, placed in the center of the thread. It is necessary to monitor the voltage, its indicator should not exceed 5 V. If the device shows 0 or 12 V, then there is a gap in this place.
- With the use of an ohmmeter - the device turns on in the "kiloohm" mode and is connected to the opposite terminals of the heater. You should moisten the cotton wool and draw along the thread. In the place where the arrow will twitch, and there is a gap.
Definition of malfunction of heating of back glass
You can repair the heater in a variety of ways, for example, purchase a special kit for repairing rear window heating filaments.
You can fix the system using a repair kit, conductive paste and folk methods. The main difference between all options are the materials that are used during operation.
Repair materials
By purchasing a repair kit, the driver has the opportunity to repair the heating filament up to 10 cm. Materials used in these kits:
- pattern with threads;
- thermally active polymer resin in a can.
Materials for repairing heated rear window
Work is carried out strictly with the heating system turned off. Having determined the place of damage, it is necessary to remove the protective film from the template and attach it to the found place. The polymer material is applied with a brush, and after drying it is repeated several times. After completing the work, the stencil is removed and it is advisable not to turn on the heater during the day.
In the case of using a conductive paste, you may only need a building hair dryer, which speeds up the drying of the material.
The materials used in the "folk" methods of repairing the heater are paint (glue) and shavings, metal for soldering the damaged area. As a rule, the paint is selected in accordance with the color of the threads and combined with chips, adhering to a 1: 1 ratio. To work, you need a stencil on which the mixture is applied (with the device turned on). The advantage of this repair method is that there is no need to wait for drying during the day. The driver can immediately go after the work is done. Zinc chloride is suitable for soldering.
How to restore heat with glue
Quite often, drivers use conductive adhesive to repair the heated rear window. The material is mixed with shavings, which are mined with a file or a copper-brass bar. The ratio is 1:1. The result is a soft dough consistency. Using electrical tape or adhesive tape, a stencil is made, and the prepared mixture is applied to the site of damage. After the procedure, you do not need to wait for the materials to dry and you can immediately move on.
Heated Rear Window Repair Adhesive
What to do with contacts, and other methods
If the contacts were damaged in the heating system of this element of the car, then it is best to use the soldering method. This method is the most reliable and will help to forget about this problem for a long time. Zinc chloride works great. It is recommended to take solder with a minimum tin content. After completion of work, the glass must be rinsed well with water to remove chemical residues.
Heat recovery price
In fact, repairing the heater is quite simple and inexpensive. Using the "paint + chips" method, the driver will incur minimal costs by purchasing paint of the desired color (or using the available material) and preparing sawdust. If you buy a repair kit, it will be much more expensive. The cost also depends on the manufacturer of the conductive adhesive. It can be a well-known and expensive company Keller or a cheaper manufacturer - Loctite. An alternative would be the glue of a Russian company.
The terminals from the heating system are connected to ground. A wire extending from the positive is connected to a brush made of a metal rod. With the resulting electrode soaked in the solution, the driver must diligently rub the sectors in which the appearance of breaks in the conductive element is noted. Areas with minor damage to the threads after such a procedure are completely tightened with copper. The ends of large gaps will have to be pre-processed with a soldering iron. With its help, an additional jumper is attached from a very thin wire.
Troubleshooting the Heater with Conductive Adhesive
Progress:
- Preliminary cleaning of damaged areas. For this, you can use the usual . At the end, wipe the damaged areas dry and degrease them with alcohol.
- Use adhesive tape to protect the area where the conductive adhesive is to be applied.
- Conductive adhesive, consisting of two components, is kneaded in a separate bowl, strictly following the instructions on the package.
- The adhesive layer must not exceed 2 mm. The curing time of the conductive layer is 30 minutes.
- Work with a cotton swab or brush.
- Removing tape at the end of the work done.
For relax repair work in special repair kits, which include a stencil and conductive glue. Their price ranges from 300 rubles. You can also use DD6590 glue instead. It looks like a syringe with an activator, a wooden applicator and a napkin soaked in alcohol.
Knowing how to fix the rear window heating system and what tools to use, the motorist will never drive with icy windows, and therefore,.