- Windows general
- Repair windscreen damage
- Replacing the windscreen
- rear window
- Windscreen heating and demisting
- Double glass
- Rain / Light sensor
- Tints / Blinding the windows
Windows in general:
Of course, the windows in the car mainly provide good visibility. In addition, the windows also have a protective effect. The windshield must not obscure the view if an object (such as a stone) hits the window and damages it. The side windows must not splinter if broken, which could lead to injuries.
All windows also have UV protection as standard. The windows are then slightly green or blue tinted, so that UV radiation, and therefore also heat, is kept out. The UV protection provides a tint of about 20% and withstands a temperature of up to 20°C.
This page describes the different types of windows and their applications.
Nowadays, windscreens are always glued on passenger cars. In older passenger cars and some modern trucks, the window is clamped in rubbers in the rebates of the body. The bonded windows (both the windscreen and the rear window) provide extra rigidity for the body. Due to the special window kit, the windows then form one whole with the body, as it were.
In the past, windscreens were made of tempered glass. When an outside object (such as a stone) collided with the windshield, there was a good chance that the entire window shattered. Small fractures then appeared over the entire pane surface, which completely obscured the view (see the image).
Today's windscreens are made of laminated glass. This has the advantage that an asterisk or a crack is formed in the event of an impact. The view is never completely obscured as with tempered glass and in the case of minor damage, the chance that the window can be repaired is very high. Laminated glass consists of two parts with a layer of transparent foil in between. The thickness of the inner and outer part of the pane are both 3 millimeters. In case of damage, small hairline cracks appear in the outer part of the pane.
Repairing damage to the windscreen:
The image below shows damage to a laminated pane. A stone has bumped into this, causing small hairline cracks in the outer part of the glass. Because the light now reflects against the cracks, these parts are darker. Damage as shown in the image below can easily be repaired up to a size of a 10 Euro cent coin.
During repair, special repair fluid / resin is pressed into the cracks under pressure. Because the space between the cracks is filled, the light no longer reflects against the 2 separate parts of the glass. The damage can be made almost invisible in this way. The chance of the window tearing through is also minimized. A windshield repair is never completely invisible, because the place of impact always remains visible as a stone chip. However, the place of impact can be removed as far as possible by means of polishing.
In case of excessive damage or cracks, the windscreen can be replaced. According to the inspection requirements for the APK, damage in the field of view of less than 20 mm is allowed. If the damage is greater, or if the cracks branch out in various directions, there is a good chance that the windscreen will be rejected. The windshield needs to be replaced.
When replacing the windscreen, the old window is cut out. The kit is cut from the rebates with special knives or cutting wire. The windscreen is then lifted out and the old sealant residues are removed. Any damage from removal should be touched up to prevent rust in the future. The rebates must also be cleaned and degreased. After that, the sealant layer is usually applied to the windscreen. Sometimes this is first applied directly to the car. The windscreen is put in place as soon as possible after the sealant. The top of the window is secured to the roof with tape or special suction cups so that it cannot slide down before the sealant is dry.
It takes some time for the kit to dry and it is therefore advised not to close the doors when the windows are closed (due to the air pressure in the car) and to leave the car for a while (for at least 2 hours) .
If the window is not positioned correctly, the following malfunctions can occur:
- Leaks are caused by incorrect application of the window sealant
- Whistling noise can be heard while driving (The windscreen is probably too high or too low)
- After a very short time there is again a crack in the glass (The glass is mounted under too much tension)
When these faults occur, you can contact the company where the window was replaced for warranty.
Damage to the other car windows:
The side windows and the rear window of the car are made of tempered glass. When broken, the rhombus must fall apart in the form of very small grains. These granules must not be sharp, because the occupants could be injured additionally in a collision. The occupants must also be able to smash the window easily if, for example, the car falls into water. The image below shows what a side or rear window looks like after it has been smashed. The parts that are still present crumble easily when gently pressed against. Of course there is a risk of injury if the glass is handled, but this is a lot safer than shards of glass.
The side windows can be clamped or glued. Often the windows of the rear passengers that cannot be opened (such as on a 3-door car) are glued. In a 5-door car, the rear windows are often partly clamped in the rubbers (small window) and partly mounted on the window mechanism (so that it can open and close). The latter also applies to the front doors. More information about the attachment to the window mechanism can be found on the page window mechanism.
There are exposed wires in the rear window that heat up when a current flows through them. The moisture on the rear window will quickly evaporate when the rear window heating is switched on. The wires of the rear window heater carry the full on-board voltage of 12 volts. The heater needs approximately between 10 and 15 Ampere to function.
If one or more wires have been damaged, part of the heating may no longer function. When the rear window defogger is switched on, a damp spot will remain near the relevant wire. This is in the entire length of the wire. When the wire is interrupted, no current can flow through it, so the wire will no longer heat up. The most common cause of a broken wire is after an object has been rubbed against it that was in the trunk.
The voltage on the wires can be measured with a voltmeter. The plus pin of the voltmeter can be held on the wire and the minus pin must be held against the vehicle's ground. The voltmeter can be used to determine where the wire break is located.
Repair kits are available with which the interrupted wires can be reconnected by means of a conductive liquid. The conductive liquid in the break can be lubricated with a brush. After the liquid has dried, the rear window defogger will function again. However, the place of repair remains visible.
Nowadays, antennas are increasingly being incorporated into the rear window. By installing antennas at several points (sometimes also in the rear side windows) an optimal radio reception will always be obtained. In that case, the radio selects the strongest signal.
Windscreen heating and demisting:
In winter, the windows can mist up from the inside. The windshield demist, which is mandatory for every car, blows warm air against the window to evaporate the moisture. The demisting will of course only work once the coolant has warmed up. The rear window of every car is equipped with rear window heating. The rear window contains all glow coils (these are the horizontal stripes that can be seen) which heat up when current flows through them. The rear window defogger button is present on every car and the windscreen defroster button is also present on cars with automatic climate control. On cars without automatic climate control, the rotary knobs must be set to the windshield and to warm.
The windscreen defroster works by means of the warm air that is blown against the windscreen through the grille (widthwise the dashboard). The side windows are also demisted, namely via the smaller grids in the dashboard that cannot be adjusted (see image below). These grids guide the air at a certain angle, so that the entire glass surface is freed of condensation.
If the windscreen defroster does not function (eg because the heater motor is defective, or the valves of the heater housing are not adjusted), this is a rejection point for the APK. The MOT always checks the airflow along the windscreen. If the windscreen continues to mist up, there is often a moisture problem (water leakage through the door seals or the window mechanism or the door foil), or the cabin filter is clogged with damp leaves.
On some luxury cars, the windscreen is also equipped with heating wires. These heating wires often run in a vertical direction over the windshield and are barely visible. The advantage is that the coolant does not have to be warmed up before the windscreen demisting system with air can do its job and that any frozen windscreen wipers can now also thaw.
Sometimes double glazing is also used in cars. This often concerns cars from the more expensive segment. Usually this is for extra security. There are then 2 panes, each 3mm thick, placed against each other. Between the windows is a special foil to prevent moisture and condensation between the windows. The advantages are that the noise from outside decreases considerably and that double glazing has a strong insulating effect. The disadvantages are that the complete door has to be adapted by the constructor; the window mechanism, the window motor and the door hinges must be made heavier and the door panel must be adapted. Also, double glazing cannot easily be broken when an emergency occurs, for example when the car falls into water.
Rain / Light sensor:
The rain/light sensor is mounted behind the interior mirror on luxury cars. This sensor registers raindrops and the light intensity. The functions of the windscreen wipers and the lighting of the car are controlled by these sensor values. More information about the RLS later.
Tints / Blinding of the windows:
By default, car windows are tinted up to 20%. This can often be recognized by a green / bluish sheen. The standard shade is heat resistant, because the UV radiation is partly blocked. The temperature with a tinted window can decrease by up to 20°C. Windows can also be additionally tinted. This is usually done by sticking foil against it. This foil is often dark gray in color and enhances the UV-resistant effect. Also, the windows are often tinted for cosmetic reasons; a car with tinted windows often looks neat and sporty.
There are limits to the extra tinting of the car;
- The windscreen and the front side windows may be provided with foil, provided that the light transmission is at least 55%.
- The side windows of the rear passengers, any side windows in the trunk of a station wagon and the rear window may be tinted without a maximum value. These windows may even be covered with black foil that does not allow light to pass through.