Wipers, bulbs and window regulators

What parts make up a wiper system?

Trico, a wiper maker, says the key parts of a wiper system are the wiper linkage, a DC electric motor and the wiper arms that drive the blades. Trico says that when the wipers are switched on with the control on the steering column, an electric motor starts and powers a mechanical linkage that moves the arms and blades back and forth.

Trico says the blades sweep away debris by pressing evenly against the glass. A 2023 U.S. Kia owner's manual, for one model, says the wipers and washers remove foreign substances from the windshield and rear window, helping to maintain visibility. Other makes and models may differ.

Trico says the wiper motor is typically found under the hood near the firewall, and that the linkage turns the motor's circular motion into back-and-forth movement. Trico says the spring in the wiper arm supplies the down force on the blade. Trico calls that down force critical for keeping the blade in contact with the glass at all vehicle speeds.

Trico describes a conventional blade as frame-and-truss construction with six to eight pressure points, and a beam blade as having what it calls an infinite number of pressure points. Trico also says beam blades are designed to match the curvature of modern windshields.

The washer system is part of the same job. Trico says it is made up of a reservoir, a pump, hoses and washer nozzles located on the hood, leaf screen or wiper arms. Trico says fluid flow can be blocked if the nozzles are clogged or if the hoses are worn or pinched. The Kia manual says washer fluid should be checked and refilled periodically so that it does not run out.

What do sun, heat and cold do to the rubber on a wiper blade?

Trico says long periods of UV exposure can dry out the rubber elements in wiper blades, and it names this as a potential cause of streaks for drivers in a sunny, dry climate. Trico says dried out blades have a very difficult time gliding smoothly and snugly across the windshield. In a separate article Trico says traditional rubber blades can wear out fast in hot or cold weather and under strong sun, and that sunlight and ozone can make them dry or crack.

Trico says extreme heat or low temperatures can cause chatter, which it describes as the loss of ability to pivot smoothly back and forth. Trico says permanent set, caused by exposure to extreme heat, occurs when the rubber element is fixed in one position. Trico says frigid temperatures can stiffen the element, and it calls that cold set. Trico says cold set limits wiping ability. Trico also says regular rubber can become stiff in the cold and can deform and become set in the heat.

Trico says its own blade materials offer ozone resistance to protect the blades from hardening, drying out and cracking, and heat resistance to maintain blade flexibility. Trico says synthetic materials often resist extreme weather better than natural rubber, while natural rubber offers a balance of durability, ozone and UV resistance and heat tolerance.

Trico says silicone elements resist temperature swings and UV radiation. Trico also says silicone can leave a thin film of residue on the windshield, and that over time this film can result in slight smearing or reduced visibility under certain lighting conditions. The Kia manual says that when the wipers no longer clean adequately, the blades may be worn or cracked.

What do streaks, squeaks and smearing point to?

Trico says blades start leaving streaks where the rubber is no longer snug against the windshield. Trico says bent or damaged blades are less effective at clearing rain, snow, sleet and other road elements. Trico says a tattered rubber element or a bent blade can leave a wiper ineffective.

For squeaks, Trico lists possible causes including: debris or grime build-up, a dry windshield from a lack of washer fluid, and worn or damaged rubber letting the wiper structure touch the glass. Trico says window cleaner deals with the grime. Trico says that structure touching the glass can potentially damage it. Trico says the appearance of streaks or squeaking noises are clear signs the blades should be replaced.

At speed, Trico says wind and airflow can generate enough force to lift a wiper blade away from the windshield, and it says this can impair visibility. Trico calls the separation wind lift and says conventional blades are not designed with wind resistance in mind. In winter conditions, the Kia manual says heavy snow or ice should be cleared from the windshield before the wipers are used.

The manual says that without clearing it first, the wiper and washer system may be damaged. The manual also says not to use the washer in freezing temperatures without first warming the windshield with the defrosters, because the washer solution could freeze on the glass and obscure vision. It says wipers may stop when snow builds up, and it calls that normal rather than a failure.

The motor and arm can show their own signs. Trico lists signs of wiper motor failure as louder motor noise, a slowdown in wiper speed, intermittent operation, or wipers stalling or stopping during use, sometimes in the middle of the windshield.

Trico says a loose nut on the wiper arm attachment can cause intermittent arm travel, or an arm that stops between its up and down motion. On timing, Trico says a general rule is to change wiper blades every six months, and that extreme conditions could call for a shorter interval.

Headlight dimming, bulb pairs and lamp assemblies: what the sources say

Sylvania, a bulb maker, says headlights dim over time. Sylvania says a headlight bulb can lose up to 50 feet of visibility before burnout. On its halogen and HID product listings, Sylvania advises always replacing bulbs in pairs to ensure equal brightness and color. On its LED listing, Sylvania gives the same advice and adds performance to the list. The pair advice in this section comes from that bulb maker's product pages.

The Kia manual gives a rule about what goes into the socket. It says a burned-out bulb should be replaced with one of the same wattage rating. The manual says using a different rating may cause damage to the fuse or electric wiring system. The manual also says non-genuine parts or substandard bulbs may lead to a blown fuse or other wiring damage.

The manual covers the lamp assembly as well. It says the headlamp lens should not be cleaned with chemical solvents or strong detergents. It says moisture can appear inside a lamp lens after a car wash or driving in the rain, and describes this as a natural event caused by the temperature difference between the inside and outside of the lamp.

The manual says the moisture would disappear if the vehicle is driven with the headlamp on, and that persistent moisture should be checked. On aim, the manual says headlamp aiming should be adjusted after an accident or after the headlamp assembly is reinstalled. Sylvania says it is important to have properly aimed headlights, keeping light where you need it on the road.

How do halogen, HID and LED lights differ, and what do drivers notice?

Sylvania's product listings describe a halogen headlight bulb as a filament working with a halogen gas mixture. Its HID listings say xenon gas produces a white light and that the bulbs are tuned for quick warm-up. Sylvania labels its HID bulbs as not a halogen replacement, and as a direct replacement for vehicles equipped with HID. Sylvania's LED listing says advanced thermal management keeps the LEDs cool, and it labels that LED line as replacement bulbs for fog lights and powersports only.

The Kia manual describes its LED stop and taillamp as an integrated unit. It states that the LED lamp cannot be replaced as a single unit because it is an integrated unit, and that the LED lamp has to be replaced with the unit. The manual says not to install extra lamps or LEDs on the vehicle. It says added lights may lead to lamp malfunctions and flickering. It also says the fuse box and other wiring may be damaged.

On flicker, the Kia manual says it is normal for an operating lamp to flicker momentarily because of a stabilization function in the vehicle's electronic control device. It says that if the lamp continues to flicker several times or turns off completely, there may be an error in that control device. The manual also says that if a bulb or lamp connector is removed while the lamp is on, the fuse box's electronic system may log a malfunction, and that a lamp malfunction may be recorded as a Diagnostic Trouble Code.

What do LED bulbs do on a car built for standard bulbs?

Sylvania's FAQ says replacing traditional miniature incandescent bulbs with LED bulbs can occasionally trigger dashboard warning lights or unexpected hyperflash. Sylvania says some vehicle computers are programmed to look for a standard incandescent bulb by sending out a low-voltage pulse. Sylvania says that when an LED is installed, the computer can think no bulb is present and trigger a dashboard warning light.

Sylvania also says many modern vehicles use electronic switches in place of mechanical contact switches. Sylvania says those electronic switches can leak a tiny amount of current through an LED and make it glow after the car is switched off. Sylvania says this will not damage the LED bulb or the vehicle. A third pattern Sylvania describes is on vehicles with a CK-style socket, where after an LED swap either only the brake light or only the tail light works.

Sylvania's FAQ also covers lens color. Sylvania says the bulb should match the color of the lens that covers it. Sylvania says that a white LED behind a red tail or brake lens will look pink or orange, and that a white LED behind an amber lens will look greenish.

What does a power window regulator do inside the door?

A technician-written article on Oards says the window regulator is the hidden mechanism inside the door that moves the glass up and down. It says the regulator converts the motor's power into the movement needed to raise and lower the glass. It lists the basic components as the motor, a system of cables or tracks, and mounting brackets. It says most modern cars use cable-driven regulators, where steel cables wind around pulleys, and that some use a scissor-type mechanism with metal arms.

AA1Car, a technical article site, describes the same range of designs. It says some power windows use a scissors linkage with a crank mechanism. It says others use a plastic chain or strip to raise and lower the window linkage. It says others use a steel cable, and it mentions gear drive regulators as well.

The Kia manual says each door has a power window switch that controls that door's window, that the driver's door has a master switch that controls all the windows, and that the ENGINE START/STOP button must be in the ON position for the windows to operate. AA1Car says that when one power window fails to move, the most likely causes include a bad switch, a bad power window motor, or a wiring fault. AA1Car says that when none of the windows move, the fault could be a blown fuse for the power window circuit, a wiring problem, or a problem with the harness or module that controls the windows.

What do grinding, a dropped window and crooked travel sound and look like?

Oards says a window normally moves with a quiet whirring sound from the motor. It says grinding, clicking, scraping or popping is a clue that the motor or regulator is having trouble. Oards says grinding often points to worn gears inside the motor or cables rubbing on something.

It says clicking or popping typically indicates cables slipping or jumping on their pulleys, and that scraping usually indicates something binding in the tracks or the glass rubbing the door frame. AA1Car says that if you hear humming or buzzing from inside the door and the window does not move, the problem is a broken window mechanism inside the door.

On movement, Oards says a window usually gives fair warning by moving much slower than normal before it stops working completely. Oards says a window that stops partway and sticks in the same spot usually points to cables starting to fray or stretch, or to tracks with debris or damage.

Oards says a window that drops into the door panel, usually with a thud, typically means a cable has snapped or the clips holding the glass have broken. Oards says glass that tilts as it travels usually means bent or misaligned tracks, or one side of the mechanism being more worn. AA1Car says a window that lowered fine but will not come back up may be off its track inside the door.

Conditions play a part too. AA1Car says a plastic window drive becomes brittle over time and cracks or breaks, and that this often happens in cold weather, especially if ice has frozen the window shut and the motor tries to force it open. AA1Car says trying to lower a window that is frozen shut can blow the fuse or break the mechanism inside the door.

The Kia manual says power windows may not work properly in cold and wet climates because of freezing. Oards says heat can warp parts and affect lubrication, and that sand, leaves and grime in the window channels can bind the mechanism. Oards says manually pushing or pulling on a stuck window can break cables, bend tracks or damage the motor.