2014 Nissan Altima Windshield Wipers

The 2014 Nissan Altima, a popular mid-size sedan, relies on a carefully engineered windshield wiper system to ensure clear visibility in inclement weather. While seemingly simple in function, the mechanics and electronics that drive these wipers represent a microcosm of automotive engineering principles. This guide will dissect the Altima's windshield wiper system, providing a detailed look at its components, operation, and some common maintenance considerations.

System Overview

The wiper system in the 2014 Altima comprises several key components working in concert:

Wiper Motor: The heart of the system, providing the rotational force to drive the wiper arms.
Wiper Linkage: A mechanical assembly that translates the motor's rotary motion into the oscillating motion of the wiper arms.
Wiper Arms and Blades: The visible components that physically clear water, snow, and debris from the windshield.
Wiper Switch: Located on the steering column, allowing the driver to control wiper speed and activation.
Wiper Control Module (Integrated into BCM): The electronic brain, managing wiper operation based on driver input and, in some models, sensor data.
Washer System: Includes a washer fluid reservoir, pump, and nozzles to spray cleaning fluid onto the windshield.

The Wiper Motor: The Source of Motion

The wiper motor is typically a small, DC (Direct Current) permanent magnet motor. These motors are chosen for their compact size, relatively high torque output at low speeds, and ability to operate reliably in a wide range of temperatures. Inside the motor, a rotating armature interacts with a magnetic field generated by permanent magnets. When current is applied, the armature spins, driving a worm gear.

The worm gear is crucial for several reasons. Firstly, it provides a significant gear reduction. Wiper motors operate at relatively high RPMs, but the wipers themselves need to move at a much slower, controlled speed. The worm gear achieves this speed reduction while simultaneously increasing the torque. Secondly, the worm gear provides a degree of self-locking. When the motor is off, the wipers are held in their parked position, and the worm gear makes it difficult for external forces (like wind) to move them. This self-locking feature ensures the wipers remain securely in the park position.

The motor's speed is controlled by varying the voltage applied to it. Lower voltage results in slower rotation, while higher voltage increases the speed. The wiper control module regulates this voltage based on the driver's selected speed setting.

The Wiper Linkage: Converting Rotation to Oscillation

The rotational motion from the wiper motor is transformed into the back-and-forth (oscillating) movement of the wiper arms by the wiper linkage. This linkage is a clever arrangement of rods, pivots, and levers. Here's how it generally works in the 2014 Altima:

The worm gear on the wiper motor shaft connects to a crank arm. This crank arm rotates in a circle as the motor spins.
The crank arm is connected to a connecting rod. As the crank arm rotates, it pushes and pulls the connecting rod back and forth.
The connecting rod is, in turn, linked to a pivot arm. This pivot arm is attached to a central pivot point on the car's body. The back-and-forth motion of the connecting rod causes the pivot arm to swing from side to side.
Finally, the pivot arm is connected to the wiper arms via additional connecting rods or levers. This translates the swinging motion of the pivot arm into the oscillating motion of the wipers across the windshield.

The geometry of the linkage is carefully designed to achieve the desired wiper coverage area and wiping pattern. The length of the arms, the placement of the pivots, and the angles between the components all play a crucial role in determining how the wipers move across the windshield. Subtle variations in these dimensions can significantly alter the wiper's performance.

Wiper Arms and Blades: The Business End

The wiper arms are spring-loaded to apply consistent pressure to the wiper blades, ensuring good contact with the windshield surface. This pressure is essential for effective water removal. The arm itself is typically made of steel or aluminum to provide the necessary strength and durability. The design and weight of the arm also play a role in preventing wiper chatter at higher speeds.

The wiper blades are made of flexible rubber compounds designed to conform to the curvature of the windshield and effectively squeegee away water. The rubber compound must be durable enough to withstand repeated friction against the glass and resistant to degradation from sunlight, ozone, and temperature extremes. Modern blades often incorporate features like:

Graphite coating: Reduces friction and noise.
Aerodynamic spoilers: Help maintain blade contact at higher speeds by reducing lift.
Beam blades: Contain an integrated spring steel beam that distributes pressure evenly along the blade's length, eliminating pressure points and improving wiping performance.

Wiper Switch and Control Module: The Brains of the Operation

The wiper switch on the steering column provides the driver with control over the wiper system. Typical settings include:

Off: Wipers are inactive.
Intermittent: Wipers operate at preset intervals.
Low: Wipers operate at a continuous slow speed.
High: Wipers operate at a continuous high speed.
Mist: Wipers operate briefly when the switch is held in this position.

The wiper switch doesn't directly control the wiper motor. Instead, it sends signals to the Body Control Module (BCM), which acts as the wiper control module. The BCM interprets the driver's input and controls the wiper motor accordingly. In the 2014 Altima, the BCM is a central computer that manages various body-related functions, including lighting, door locks, and the wiper system. Integrating the wiper control into the BCM reduces the number of separate control modules in the vehicle, simplifying wiring and reducing costs.

The BCM uses pulse-width modulation (PWM) to control the wiper motor's speed. PWM involves rapidly switching the voltage applied to the motor on and off. By varying the duty cycle (the percentage of time the voltage is on versus off), the average voltage applied to the motor can be precisely controlled, thereby controlling its speed. For example, a 50% duty cycle means the voltage is on for half the time and off for the other half, resulting in a lower average voltage and slower motor speed.

Some 2014 Altima models may be equipped with rain-sensing wipers. These systems use a sensor mounted near the rearview mirror to detect the presence of water on the windshield. The sensor sends a signal to the BCM, which automatically activates the wipers and adjusts their speed based on the amount of rainfall. The rain sensor typically works by emitting infrared light and measuring the amount of light reflected back. When water is present on the windshield, it interferes with the reflection, triggering the wipers.

Washer System: Adding Cleaning Power

The washer system complements the wipers by providing a means to clean the windshield of dirt, grime, and insects. The system consists of:

Washer Fluid Reservoir: Holds the cleaning fluid (typically a mixture of water and detergent).
Washer Pump: An electric pump that draws fluid from the reservoir and delivers it to the washer nozzles.
Washer Nozzles: Small nozzles mounted on the hood or near the wiper arms that spray the washer fluid onto the windshield.
Hoses: Connect the reservoir, pump, and nozzles.

When the driver activates the washer system, the BCM energizes the washer pump. The pump draws fluid from the reservoir and forces it through the hoses to the nozzles, which spray the fluid onto the windshield. The driver typically activates the washer system by pulling or pushing the wiper control stalk.

Maintenance and Troubleshooting

The 2014 Altima's windshield wiper system is relatively reliable, but regular maintenance is essential to ensure optimal performance. Here are some common maintenance tips and troubleshooting steps:

Replace Wiper Blades Regularly: Wiper blades should be replaced every six to twelve months, or more frequently if they show signs of wear, such as streaking, skipping, or chattering.
Check Washer Fluid Level: Regularly check the washer fluid reservoir and top it off as needed. Use a washer fluid formulated for automotive use to prevent clogging and freezing.
Inspect Wiper Arms: Check the wiper arms for damage, such as bending or corrosion. Ensure the spring tension is adequate to maintain proper blade contact.
Clean Washer Nozzles: Clogged washer nozzles can be cleaned with a small pin or needle.

Common wiper system problems include:

Wipers Not Working: Check the wiper fuse. If the fuse is blown, replace it. If the fuse continues to blow, there may be a short circuit in the wiring. A faulty wiper motor or BCM could also be the cause.
Wipers Moving Slowly: Low voltage, a worn-out wiper motor, or a binding linkage could cause slow wiper movement.
Wipers Not Parking Correctly: A faulty wiper motor or a problem with the park switch within the motor can prevent the wipers from parking correctly.
Washer System Not Working: Check the washer fluid level. If the fluid level is adequate, check the washer pump fuse. A faulty washer pump or clogged nozzles could also be the cause.

Understanding the inner workings of the 2014 Nissan Altima's windshield wiper system provides a valuable insight into automotive engineering principles. From the efficient DC motor to the cleverly designed linkage and the sophisticated electronic control, each component plays a vital role in ensuring clear visibility and safe driving in all weather conditions. Regular maintenance and a basic understanding of the system can help keep your Altima's wipers performing optimally for years to come.