Rear window heating repair. We repair the rear window heater on the car. Doesn't work what is the reason

Freezing and fogging rear window lead to a decrease in visibility, which limits control over the traffic situation. In the article we will consider all the heating components, as well as their possible malfunctions... We will show you how the rear window heating is repaired.

How the system works

To easily find a malfunction of the rear window heater, consider the system design. All elements are presented in the schematic diagram.

Mounting block.
Heating switch relay.
Egnition lock.
Button on dashboard... A light is installed inside the button, which lights up when the heating and ignition are on.
The corresponding icon on the dashboard, duplicating information about the included heating.
Conductive threads located on the rear window.

The principle of operation of the entire system lies in the heating effect, which manifests itself when current passes through the heating element. Such in the rear window heating system is a network of conductive threads. When the ignition is turned on in the 3rd position (On) through the fuse (in our case, F7), power is supplied to the system power button. After pressing the button, the current, lighting the control lamp, flows to the corresponding icon on the dashboard and back to the mounting block to the switching relay. After the corresponding contacts of the relay are closed, power is supplied (+) to one of the terminals of the system of conductive threads. The second terminal is connected to the car body corresponding to the negative terminal of the battery. Thus, a current begins to flow through the threads.

Now it is easier for us to understand how to repair the heated rear window. For a successful repair of a heated rear window of a car, it is advisable to be able to read electrical diagrams, since not for all cars you will find such clearly depicted elements as in the diagram provided by us.

Malfunctions

How to find the reason

All manipulations to find the cause of the breakdown should be done after checking the fuse. Also, the very nature of the breakdown can often suggest a way to troubleshoot.

For example, together with the heated rear window, the light in the button stopped working. It is likely that this is just a coincidence, as the light bulb may have simply burned out. But the contiguity speaks of the likelihood of no power going to the button. In this case, according to the above diagram, you need to check the circuit from the ignition switch, terminals 1 and 9, 2 and 4 on the mounting block, 85 and 86 relay contacts, as well as the button itself.

There is no heating of the filaments, but the light in the button works after switching on. In this case, the power to the button is exactly coming, therefore there is a breakdown in the circuit after the switch. It is necessary to check fuse F4, the heating switch on relay and the corresponding terminals in the mounting block, as well as the contacts of the heating threads.

The glass is only partially thawed, indicating that some of the filaments have broken.

Power check

To diagnose an open circuit, you need to know. In direct current (DCV) measurement mode, you need to check sequentially to see if a voltage is being applied to one or the other pins.

To check the power supplied to the relay, it must be removed from mounting block... To check, you need a multimeter (in constant current mode, up to 20 V) or a test. Turn on the heated rear window. If there is current on the 85 and 86 pins of the relay, then there is a malfunction in the relay itself or in the subsequent elements of the circuit.

To check the performance of the relay itself, it must also be removed from the unit.

You can use the multimeter in resistance measurement or so-called continuity mode. Illumination of different bulbs helps to identify + and -; some devices have a soundtrack.

To check the coil located in the relay, connect the probes to pins 85 and 86. If the multimeter shows infinite resistance, and the red indicator does not light up in the control, indicating a short circuit, then the coil is burnt out or the contacts are soldered. For the subsequent check, connect the power supply from the battery to the 85 and 86 pins. After a click, indicating that the coil is working, contact should appear between pins 30 and 87.

If you do not want to test separately the relay and terminals 85, 86 in the mounting block, check if there is voltage at terminals 10 (Ш9) and 5 (Ш8). The presence of voltage will be the fact that the relay and the tracks of the wiring block are fully functional.

If, while searching for a malfunction, you find oxidation of the contacts, clean the surface with sandpaper or a file. The repair of the heater will be completed at this point.

Finding a break in a heating element

There are many ways to detect broken conductive filaments. For searches, you can use the multimeter in resistance measurement mode. You need to measure the resistance at the beginning and end of each strand. The value should be approximately the same. If the value 1 lights up on the screen, this will indicate an open circuit. You can connect to the battery cable leads. The multimeter must be set to DC measurement mode. Attach the positive probe to the positive terminal of the heating element, and apply the negative one to the middle of each thread. The value should be equal to half of the battery charge.

To localize the place, measure in the same way, starting from the edge of the thread. Place the probes at a distance of, for example, 10 cm and work your way to the edge of the thread. In order not to damage the tinting excessively, you can solder the needles to the leads of the probes. This will allow you to discreetly pierce the film without harming the threads themselves.

DIY repair

Rear window heating repair is impossible without a special conductive compound. Special glue can be used to attach the terminals to the element. There are special repair compounds for the restoration of threads. Their cost is quite democratic, and you can find them in almost every department of automotive supplies. There are also methods for self-manufacturing conductive compounds. Heater repair is as follows:

remove the tint from the break. Use a ruler and a clerical knife to carefully cut the film only along the perimeter of the thread break;
degrease the surface;
stick the masking tape, leaving a place inside for the repair compound;
apply conductive glue;
tear off the tape. Do not wait for the composition to dry, as there is a possibility that the layer from the repair area will subsequently come off along with it.

Do not apply too thick a layer, as this will reduce the resistance and, as a result, the temperature in the repair area.

A heating element repaired in this way will continue to serve you faithfully.

Good visibility is essential for safe vehicle operation. In the autumn-winter period, the glass fogs up due to changes in air temperature, and visibility through them deteriorates. The issue of glass transparency is especially relevant at night, when visibility is already poor.

An effective way to combat fogging of car windows is to heat them. The windshield is usually heated by directed streams of warm air. The rear window and rearview mirrors are usually heated using electricity. Conductive paths made of high-resistance metal in the form of thin ribbons are applied to the glass surface from the side of the car interior. When an electric current passes through them, thermal energy is released. The glass heats up and the water evaporates. After a few minutes, the glass becomes transparent.

Heater wiring diagram

To successfully diagnose and repair the rear window heating system of a car at a professional level, it is necessary to know the wiring diagram of the heater and to understand the principle of its operation.

The photo shows typical scheme connecting the rear window heater of the car to the on-board wiring. Let's consider how it works.

The supply voltage from the positive terminal of the battery through the ignition switch, and the fuses are supplied to the heater switch and to the 30 (or 87) power contact of the relay. The negative terminal of the battery is connected to the car body, one of the terminals of the glass heater is also connected to the body. When you press the heater power button, voltage is applied to the relay coil, the relay is triggered, the power contacts close and connect the relay terminals 30 and 87 to each other. The current enters the heater, flows through a group of parallel-connected threads and returns through the car body to the negative terminal of the battery.

Rear window defogger malfunctions

The functionality of the rear window defroster is ignored until the glass fogs up or becomes covered with frost. After turning on the heater, it is suddenly discovered that after a few minutes the glass did not become transparent or that visibility appeared only through a part of the glass. Depending on the external manifestation, even without measuring instruments, one can immediately make an assumption about the cause of the failure.

It should be noted that the rear window and rear-view mirrors heater can only be switched on when the ignition key is set to the ON position. In some car models, the heater can only be turned on when running engine... This is done to avoid a strong discharge of the battery, since the rear window heater, depending on the car model, consumes a current of 10 A to 25 A. For comparison, one car headlight consumes a current of only 5 A.

The heater does not turn on

If the indicator on the button for turning on the rear window heating does not light up after pressing it, then the fuse is most likely blown or the key itself is faulty. If the indicator is on, but not a single thread heats up, then the cause of the malfunction may be a relay or connectors for connecting the heater to the wiring. In this case, according to the documentation for a specific car model, it is necessary to determine the location of these parts and replace the failed one. It is not always possible to quickly find the place of installation of the relay, but there is a way to check its serviceability in an indirect way, which will be discussed below.

Glass is slowly sweating

Sometimes there is a case when, after turning on the heater, the glass sweats for a time significantly exceeding a few minutes. In this case, if it is not very cold outside, the reason may lie in the poor contact of one of the connectors of the electrical circuit. As a result, the contact resistance increases, the current is limited, and as a result, the power released on the glass heater filaments decreases. To check such a malfunction, it is necessary to measure the voltage at the input terminals of the heater and battery with a DC voltmeter (multimeter or dial tester, included in the DC voltage measurement mode). Voltages should not differ by more than one volt.

Horizontal misting stripes remain on the glass

And finally, the most common case of a malfunction of the rear window heating system of a car, breakage of one or more threads of the heater applied directly to the glass. This type of malfunction is immediately visible on the horizontal strip of the remaining fogging on the glass after turning on the heater.

The conductive tracks on the rear window have low mechanical strength and are easily destroyed when exposed to them. Therefore, it is forbidden to remove frost and ice from the glass with a scraper. Only wipe with a soft cloth. It is also necessary to ensure that when transporting bulky items, they do not rest against the rear window. As a rule, individual heater filaments stop working as a result of their accidental mechanical destruction. After turning on the heating, stripes of fog or frost remain in the area of the damaged thread.

When renovating an apartment, I was transporting floor skirting boards in my car and did not notice how one of them rested against the rear window. After a while, when it was necessary to warm up the rear window, I saw the result of my inattention. Two strips of the heater passing through the middle of the glass did not heat up, which significantly impaired the view of the road. Upon visual inspection, on the non-working strips, one gap of about 1 mm wide was found, as in the photograph. The question arose about the need to repair the rear window heater.

How to find a broken glass heating thread

It is not difficult to determine which thread of the heater in the cliff, since in the zone of its passage the fogging does not disappear during the operation of the heater. Therefore, in order to easily find a faulty thread during repairs, it is advisable to count the threads from top to bottom and remember which one is in the cliff, so that later by visual inspection, try to find the place of its damage. But the thread break is so small that it is impossible to find it visually. Then a DC voltmeter, ohmmeter or voltage indicator will help in the search. To quickly find the place of a malfunction in a heating element, you need to imagine how it works and works.

The device of the heating element of the glass heating system

The question is logical, why does it happen that only one or several threads in the heater do not work, and the rest work? To get an answer to this question, you need to familiarize yourself with the design of the heating element.

The heating element of the rear window of the car is arranged as follows. On the lateral sides of the rear window, two conductive buses 1 and 2 are applied. To these buses, threads of high-resistance material are connected. Each of the strands has a resistance of about 10 ohms. The number of threads depends on the height of the glass. Thus, each thread is a separate heating element, the operation of which does not depend on others. The scheme of parallel connection of heating elements is applied. Such a circuit design ensures high operational reliability of the heater, since the breakage of one or several threads does not lead to a complete cessation of its operation.

Finding a broken filament heater using a voltmeter

For work, you will need any DC voltmeter with a measurement limit of 15 V. As a voltmeter, any dial tester or digital multimeter is suitable. Before starting work, you need to turn on the heater.

Since one of the tires of the heating element is connected to the car body, the negative terminal of the voltmeter can be connected to the car body; any screw or bolt screwed directly into the body will do. It is most convenient to attach the alligator clip to the boot lid lock bracket.

Since visually with a transparent glass it is difficult to find out whether the heater heats up, then by touching the positive probe of the voltmeter to bus 1, and then to bus 2, you will immediately understand this. Bus 1 should have +12 V, and bus 2 should have 0 V. It is possible that the left bus in your car will be connected to ground, and the right bus will be supplied with supply voltage. If there is no access to the tires, then measurements can be taken by touching any of the threads with a probe at the points of connection with the tires, that is, in the places where they exit from the rubber seal. In the photo, these are points 1 and 5.

Using a voltmeter, it is easy to determine which part of the heating system is faulty. If the heater is on, the on indicator on the button is on and there is 12 V on bus 1, but there is no heating, then the wiring to bus 1 is working properly. If there is no voltage on bus 1, then there is a bad contact in the supply voltage supply terminal on bus 1, or the relay is faulty. If 12 V is present not only on bus 1, but also on bus 2, then you need to look for a bad contact in the terminal for connecting the wire to bus 2 or in the circuit for connecting the wire to the vehicle ground.

Finding the location of the thread break

After checking the power supply system to the heater, you can begin to determine the location of the breakage of the heating thread. The filament is a tape resistance of about 10 ohms, and therefore the magnitude of the voltage at its different points has a different magnitude. Therefore, at point 1, the voltage will be 12 V, at point 3 - 6 V, and at point 5 - 0 V. Therefore, even without knowing which of the threads is in the cliff, it can be easily found by measuring the voltage value in the middle of the length of all threads. On the broken threads, the voltage will be 12 or 0 V. If the voltage is 12 V, then the break point is on the left, and if 0 V, then on the right.

Now it is enough to slowly hold the probe towards the break, in the place of a sharp change in voltage and there will be a gap. For example, in the photo this is a section of a thread between 6 and 7 points.

Finding the broken thread with an ohmmeter

Using a multimeter or pointer tester in the "title =" mode (! LANG: How to measure resistance">измерения сопротивления тоже успешно можно найти место обрыва нити. Включать обогреватель при поиске омметром не нужно, но проверить исправность системы подачи питающего напряжения на нагреватель, кроме проверки цепи подключения к массе, не получится.!}

If the broken thread is not known, then you need to connect one end of the ohmmeter probe to the ground terminal, and with the second, in turn, touch the middle of the heater threads. The thread on which the ohmmeter will show the resistance is twice as much and will be in a cliff. For reference, the resistance on whole strands relative to bus 1 or 2 should be 2-3 ohms. In the event of a break in the thread, the ohmmeter will show 4-6 ohms.

When the damaged thread is found, it is necessary to move the end of the probe from the center to any side. If the resistance increases when the probe moves towards tire 1, then the break is in the gap between tire 1 and the touch point of the probe. For example, in the place indicated by points 1 and 2. As soon as the probe passes the break, the resistance will sharply decrease several times. If the resistance decreases, it means that the thread break point is between the probe and the bus 2. For example, in the place indicated by points 3 and 4. Then you need to move the probe towards the bus 2, and when the resistance drops sharply, at this point there will be a break ...

Finding the location of the thread break
with Automotive Probe Tester

If a voltmeter or ohmmeter is not available, then you can find the place where the filament of the heating element is broken using a home-made automotive tester-probe, consisting of just any one LED and a current-limiting resistor. I have made such a tester for myself a long time ago, although I have any measuring devices at my disposal. A homemade automotive tester is always in the glove compartment of my car and I had to use it more than once.

Finding a broken thread with a probe tester is not much different from searching with a voltmeter. The indicator in this case will be not an arrow or numbers, but the glow of the LED.

Before starting the search for a damaged filament with a probe, it is necessary to apply a supply voltage to the heater. First, the presence of voltage on bus 1 is checked, the LED should be on, if the LED is off, then the fault lies in the supply voltage supply circuit. Next, the voltage on bus 2 is checked, the LED should not light up, if it is on, it means that there is a contact failure at the point where the wire is connected to the bus or the car body.

To find the place where the heater filament breaks, you need to slowly, lightly touching the filament, lead along it with the end of the probe. At the point at which the LED turns off or lights up and there is a thread break. For example, at point 6, the tester's LED will glow, and at point 7, it will not. In my case, the thread breaks were large and the tester was only useful for checking the quality of the repair.

Methods for repairing heating element filaments

There are several ways to restore the working capacity of the heating thread at home.

Using conductive pastes and adhesives

The simplest and most effective is with the help of special repair kits, for example, DONE DEAL DD6590, designed to repair the threads and contacts of the rear window defroster by both amateurs and professionals. The method is good in that it does not require tools and materials. It is enough to apply a little conductive paste according to the attached instructions to the place where the thread breaks from the syringe, wait until the paste hardens and the repair is completed. But such a set costs more than $ 15.

The second method is similar to the previous one. But instead of a proprietary set, purchased conductive adhesives are used, for example, "Elekont", a Moscow manufacturer. The glue is applied to the place where the thread breaks, overlapping the whole part of the thread by a centimeter on each side. To get a neat look, a stencil made of electrical tape or scotch tape is used. For reliability, the glue is applied two times. Between the layers of conductive glue, it is advisable to lay a piece of tinned copper wire with a diameter of 0.3-0.5 mm.

It is believed that a conductive paste or glue for repairing glass heater threads can be made independently by mixing paint or glue with brass sawdust in a one-to-one ratio. The resulting composition is applied through a stencil in a thin layer to the thread breakage in several layers. But the reliability of this technology has not been confirmed by practice.

Electroplating copper

Another method is the electroplating of copper. The heater filament repair method seems attractive. But from my personal experience, I can say that the reliability of such coatings at home is low. So I hesitated to use this technology.

By soft soldering

The mechanical method of restoring the integrity of the rear window heater filaments by soft soldering has become widespread. The reliability of this method was tested by me when repairing rear window heating filaments in my own car. Given below step-by-step instruction, written on the basis of my experience, will allow you to easily repair the heater thread on your own in just a few minutes with practically no financial costs.

On the advice of theorists from the Internet, I made a big mistake, tried to strip the thread with sandpaper. As a result, instead of breaking a thread with a width of 1 mm, a break of more than 1 cm turned out. The thread tape is very thin, with only a couple of tens of microns and is erased, even with the finest-grained sandpaper, instantly. The heater threads are not covered with anything anyway, and it is enough to degrease the soldering area with a rag dipped in alcohol or acetone.

If the width of the thread break is less than 1 mm, then you can do without soldering the additional conductor. In my case, the width of the gap was large, and I had to pre-prepare a piece of copper wire for the jumper. A current of about 1 A flows through one thread of the heater. Based on this, we select a wire with a cross-section of 0.17 mm 2 from the table of wire cross-sections, which corresponds to a diameter of 0.45 mm. The length of the copper jumper should be equal to the width of the thread break plus 2 cm. Before soldering, the jumper must be tinned with a thick layer of POS-61 tin-lead solder. There is no need to tin the heater thread.

In order for the solder to reliably adhere to the heater thread, before soldering the jumper, grease the thread in the soldering area with a brush with a thin layer of zinc chloride flux.

Next, the jumper is pressed against the heating thread and heats up for one second with a 12 W soldering iron. The hand is pulled to the side. The jumper should be kept on the string. Trying to pull it to check the quality of the soldering is unacceptable, it will fall off, and also tear off a piece of the heater thread. Unfortunately, it has been tested empirically. As a result of experiments, I ended up having to solder the jumper 5 cm long.

After soldering one end of the jumper, the other is pressed tightly to the thread and also warmed up with a soldering iron. After the end of soldering, in order to remove the acidic flux residues, the glass is thoroughly washed with water.

To top it off, for reliability, although it is not necessary, I covered the soldered jumper on top with a transparent superglue "Moment" based on cyanoacrylates, the heat resistance of which is about 70 ° C. The heater does not heat up above this temperature.

As a result, the time to repair a thread break with your own hands, taking into account all the preparatory work, was no more than ten minutes. The repaired threads have been in service for over three years.

Good afternoon. Today we will talk about how to repair a heated rear window. Traditionally for our site, the article contains a lot of photos and videos and is a step-by-step troubleshooting algorithm.

How does glass heating work?

I think everyone remembers the physics from the high school course. When an electric current flows through a conductor, it heats up. It is on this principle that the rear window heating works.

If you look closely at the glass, you will see contacts and current supply wires from the sides.

When a voltage is applied to these terminals, an electric current flows through the heating filaments and heats the glass, thereby making it.

Accordingly, glass heating does not work in only two cases:

heating threads are faulty
no voltage at the terminals

How to repair the heating if one or more heating threads are faulty?

This malfunction looks like this:

For repairs we need:

sandpaper with a number from 1500 to 2500, 1 sheet of any grain. It is needed to remove oxides and varnish from places of damage to the threads.
alcohol, preferably isopropyl (we will use it to wipe the glass from dust and degrease the damage)
napkins, microfiber, cotton swabs or rags (for cleaning).
conductive adhesive, in stores it is not always available, so if you are ready to wait, I recommend ordering it directly from China (we will use it to restore damaged threads).

Repair procedure:

We carefully examine the faulty heating threads and look for damage, they usually look like this:

We carefully clean the damaged areas with emery paper, trying not to touch the glass, we only clean the heating threads themselves and then next to the damage. If you rub the glass itself with sandpaper, it will become dull, but it will not come out, since the heating threads are not applied to it.

Wipe cleaned surfaces with alcohol using a cotton swab. In this case, we will remove the dust from the sandpaper and degrease the surface.

Gently apply conductive glue to the damaged areas. In order to apply the glue directly and not as a stain, it is better to use duct tape or masking tape. As shown in the video at the end of the article.

Apply conductive glue with a brush.

We wait until the glue dries, check it, make sure that everything works and enjoy the money saved….

What if the heating does not work at all?

If the heating does not work at all, there are two options. Either all the heating threads are faulty (this is unlikely, even on machines that are 30-40 years old, one or two threads heat) ... Or the wiring is faulty.

A person without special education can only check 3 things:

The location of these items can be found in the operating instructions for your vehicle.

If, after checking, by the replacement method, your heating still does not work, it is better to contact an electrician at the station of those. service.

How to repair the heating if the glass is tinted?

I don’t want to upset you, but most likely the answer is no! Since to apply electrically conductive glue, you will have to locally (locally) remove the tint anyway. I'm not sure if you can cut a piece of tinting with just a damaged thread. In any case, you will get an ugly hole in the toning….

Therefore, if you need to repair one or several heating filaments on tinted glass, unfortunately, the tint will have to be removed.

Conclusion.

As you can see, the repair of glass heating is not difficult, of course, with due care and desire.

Obviously, the easiest option is not to repair the threads, but to replace the glass, but think about how, because if the buyer sees glass from different years of production, then at least you will be told that the car was a bit.

That's all for me today. I hope that you are not left with any questions about how to repair the heated rear window. If you have any questions, or if you want to supplement the article, write comments.

Car windows should not only perform protective functions, but also ensure driving safety. To maintain an overview of the road, various additional devices are installed on the glasses. For example, a special heating system is mounted on the rear window, which prevents it from freezing and helps to quickly clear snow and ice in the cold season, as well as from fogging.

First, let's figure out what the rear window heating system of a car is. This is a special mesh made of a high resistance material that conducts current. It is applied to the glass from the inside of the car to the rear window.

Important!In the dark, the applied mesh slightly changes the view from the rear view window. The metal strands reflect the headlights of cars driving behind, creating glare. This distracts a little from the road and may cause an accident.

On different cars the heating system may differ slightly, but in principle it is approximately the same for all models. It includes the following key elements:

heating element of the rear window heating system;

A control lamp that signals the system is turned on;

System switch;

Ignition switch;

Mounting block.

The system is activated only when the ignition is on. To turn on the system, you must press the corresponding button. Power is supplied to it through a special relay. After switching on, another relay is activated - heating, connecting the heating element. As soon as it starts to work, the control lamp of the heating indicator comes on.

The heating element itself can be made in different ways. But, as a rule, it is made in the form of a mesh of thin nickel threads. They are connected to the busbars on the sides of the glass. Each of the buses on one side receives a voltage of 12 V, and on the other is shorted to ground.

The threads themselves are attached to the glass with special glue. Sometimes the glass is first coated with a spray, say, aluminum, and a mesh is attached on top of the glue and covered with a light-transmitting film.

What spare parts and tools need to be prepared for heating installation

As can be seen from the diagram of the structure of the heating system, it is quite simple to equip a home-made rear window heating. For this case you will need:

actually the rear window;

Electric heating threads;

Approximately 5 meters of blue wire and 7 meters of red;

On / off switch;

Pads;

Relay (4 contacts for 30 A);

Heat shrinkage;

Ring-shaped union contacts for a stud bolt;

Terminals ("mom", "dad").

To install the system, you will need the following tools: electrical tape; pliers; pliers; screwdriver.

Important! The filaments are quite thin and therefore susceptible to mechanical damage. You need to work with them very carefully so as not to damage them during the installation phase. Any external influences after installation can also lead to rupture of the thread.

Heater installation steps

The question of how to connect the rear window heating is solved in two stages, especially if the work is carried out in the cold season. First you need to collect the blanks. This can be done even at home, and only after that go to the garage to the car to install the assembled system.

Collection of workpieces

This is the shortest stage. First, we take the pads, and if wiring is installed on them, we remove them. Having crimped the wires with the "mother" contacts, we fold the new block. After that, you need to fold the relay by pressing the connector rings. We make a wire with which we will connect heating to the body.

Heating installation in a car

Now you can proceed with the actual installation. To do this, remove the dashboard and pads. Be sure to remember their location so that you can later install them in the same order. To prevent a short circuit, the battery terminals must be removed in advance.

Determine where you will have the switch and relay. Connect the power, route the wires to the fuses under the dashboard. Find a 16A fuse and connect the positive wire that comes from the relay to it. The wire from the switch with the "+" sign must be connected to an 8 A fuse. All these wires are fixed to a common bundle of wires. Carefully remove the switch from the dashboard and, having connected the block, insert it back.

The final stage is the conduction of wires to the glass, which will be heated. A wire with a "+" sign is laid where it is convenient for the driver. Practice shows that its most convenient location is together with the main bundle of wiring.

Now you need to form a "mother" and insulate the wire with tape. After that, it is necessary to connect the negative heating wire to the rack housing and the body. Then you can replace the panel, mats and connect the battery.

During installation, the question often arises of how to glue the rear window heating terminal. It is ideal to solder it with rosin or acid. But this job requires some skill. If they are not there, then the part can be glued with a special conductive glue. It usually consists of silver shavings with hardener and epoxy glue.

Did you know?You can make your own conductive adhesive on silver. To do this, mix in equal parts a 1% formalin solution with nitric acid silver, and then add five drops of 5% ammonia to the mixture. The resulting black precipitate of silver must be removed with distilled water and a filter. The mixture is dried at a temperature of 105–150 ° C, to which the filtered powder is then added.

Before installing the terminal to a strip of foil, the strip is sanded from all sides, tinned. Having soldered a terminal to it, the other side is smeared with glue and pressed to the right place on the glass so that all excess glue comes out. This ensures good contact. The glue dries up within 24 hours. It is not recommended to use the heater during this time.

How to check if the heating is installed correctly

After installing the system, the next question is how to check if the heated rear window is working? To find out how successful all the manipulations described above were, you need to turn on the ignition, then heating and wait about 5-10 minutes. Then inspect the glass for system performance.

If installation is not very successful, individual filaments may not heat up. In winter, this can be noticeable with ice that does not melt. In warmer months, you can check the rear window heating filaments with a tester. It can be used to determine the integrity of the thread. If it turns out to have gaps, it must be replaced.

Did you know? Most often, an ohmmeter is used as a tester. But today this unit is a thing of the past, and instead a more versatile device is used - a multimeter.

If the system does not work completely, that is, not a single thread heats up, the problems may be as follows:

fuse malfunction;

Switch malfunction;

Poorly connected tips;

Malfunction in the wires;

The contact of the glass heating element is not connected.

As you can see, the question of how to make the rear window heating is easy to solve. First you need to assemble the entire system, and then connect it in the correct sequence to the rear window. The process is quite simple and every motorist can handle it.

You will need

- voltmeter;
- low-tin solder and zinc chloride;
- graphite powder, iron filings, nitro varnish, epoxy;
- silver sawdust and nitro-glue;
- copper sulfate solution, cloth, long copper wire;
- electrically conductive adhesive

Instructions

Find damage in the heating filaments using a voltmeter. To do this, connect one contact of the device to the busbar, and smoothly drive the other along the idle strip. Another method of finding a broken thread: turn on the heating on the fogged glass. In this case, all the glass will quickly sweat except for the place of damage. This method is simpler than the previous one, but it is not accurate and does not always work.

Regardless of the chosen repair method, first clean the damaged area from the varnish until a metallic sheen appears. It is more convenient to do this with a bent wire. Degrease in any way. Having soldering skills, solder the damaged area with soft low-tin solder such as POS-18 or POSS-4-6. Use zinc chloride as a flux. If there is damage over a long stretch, solder a thin copper or silver strand from a suitable piece of wire.

To repair using another method, coat the damaged area with a mixture of graphite powder and a small amount of epoxy glue (resin). To make the work better, install a strong magnet on the back of the glass, and put small metal filings in place of the area to be restored. They will restore the contact of the threads. After repair, treat the damaged area with nitro varnish. Remove the magnet after the varnish is completely dry. When applying sawdust, try to hit the conductor strip as accurately as possible, and not the entire surface opposite the magnet. This will help make the repair site invisible.

For the third method, take silver filings. Prepare them by filed off the alloy of the contact of the unnecessary power relay. Pour sawdust into the fold of a sheet of paper and add a drop of nitro glue. With the end of a knife, quickly roll out cylinders 1 mm in diameter and 2-3 mm in length from sawdust. Apply it to the damaged area and crush, pressing firmly on the sawdust. Remove excess.

Another method is perfect for restoring a damaged area or the entire heating thread. Prepare a solution of copper sulfate, consisting of 6 parts of water, two parts of powdered sulfate and one part of electrolyte for the battery. Mix thoroughly. Take a thick, long copper wire from the positive terminal of the battery to the glass with threads. Wrap a piece of fabric 1-2 cm wide and 10-15 cm long around the end of the wire and secure in any way.

With the other end of the wire connected to the positive terminal of the battery, soak the wound cloth in the prepared solution. Start rubbing vigorously at the break for 1–2 minutes. This will start to deposit copper around the intact filament. The coating of copper will look like patterns on frosty glass. When restoring the entire thread, start from the place where it is connected to the side live parts. This method is cheap, affordable, and has a high durability of the restored area. On the other hand, it is quite long-lasting.

For a more modern restoration method, purchase a special electrically conductive adhesive. When buying, consult with the seller. Use the stencil supplied with the product to restore the filament. Apply glue to the damaged area with a soft brush through a stencil and dry for 10-15 minutes.