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Porsche > 911 & 912 (1965-1989) > Electrical & Relays >

Wiper Mechanism

Wiper Mechanism

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Rear window wiper harness. Porsche 911 1974-89 LHD - 91161202501 - BP PS9283, RD-911.612.025.01, 1698250110
1
Rear window wiper harness. Porsche 911 1974-89 LHD
91161202501/1
Product Information
Product Information
Harness for the rear window wiper

Runs through the tunnel to the rear wiper motor
Does not include diode

oematch

Fits:
Porsche 911 1974-89 for LHD cars

Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.

91161202501
91161202501

The product you are viewing cross references to these numbers
Relay Windscreen Wiper Interval. Porsche 911 1974-75 - 91161814600 - 3.208.200
2
Relay Windscreen Wiper Interval. Porsche 911 1974-75
91161814900/1
Product Information
Product Information

Wiper Interval Relay 

The OE Match Wiper Interval Relay is a high-quality OEM-style replacement. This relay controls the intermittent wiping function, ensuring your windscreen wipers operate at the correct timed intervals during light rain and changing weather conditions.

Fits:

  • Porsche 911 1974-1975 2.7L / 1976-77 3.0 Carrera
  • Porsche 911 1975 3.0L Turbo (930)

Diagram ref no 34

Manufactured to match the original specifications, this OE Match relay provides dependable performance, direct-fit installation and reliable operation, making it the ideal replacement for ageing or failed original relays.

What Does the Wiper Interval Relay Do?

The wiper interval relay is an essential component of your Porsche's electrical system. It controls the timing circuit that activates the intermittent wipe feature, allowing the wiper blades to pause between sweeps instead of operating continuously.

By regulating the delay between each wipe cycle, the relay helps maintain clear visibility during drizzle or mist while reducing unnecessary wear on the wiper motor and blades.

The relay is responsible for:

  • Controlling intermittent windscreen wiper operation.
  • Delivering consistent timed wipe intervals.
  • Sending electrical signals to the wiper motor.
  • Providing smooth, factory-correct wiper performance.
  • Improving visibility and driving safety in variable weather conditions.

Why Do Wiper Interval Relays Fail?

Electrical relays naturally deteriorate over time, particularly in classic vehicles where components may have been in service for decades. Heat, vibration and moisture can all contribute to internal wear and eventual failure.

Common causes include:

  • Burnt or worn internal electrical contacts.
  • Ageing electronic components.
  • Corrosion caused by moisture ingress.
  • Heat damage from years of continuous operation.
  • Fatigued solder joints and internal circuitry.
  • Oxidised terminals leading to poor electrical connections.

Original relays fitted to 1974-1975 Porsche 911 models are now approximately fifty years old, making replacement a sensible preventative maintenance upgrade.

Symptoms of a Faulty Wiper Interval Relay

A failing relay can cause several noticeable problems, including:

  • Intermittent wipe function no longer operates.
  • Wipers only work on continuous settings.
  • Irregular or inconsistent wipe intervals.
  • Delayed or erratic wiper activation.
  • Wipers stopping unexpectedly during operation.
  • Audible relay clicking without correct wiper movement.
  • Complete loss of intermittent wipe functionality.

Replacing the relay is often the quickest and most effective way to restore normal operation.

When Should the Relay Be Replaced?

The OE Match Wiper Interval Relay should be replaced whenever intermittent wipe performance becomes unreliable or electrical testing confirms relay failure.

Many Porsche owners also choose to replace ageing relays during restoration projects or preventative maintenance to improve long-term reliability and reduce the risk of electrical faults.

A new relay helps restore dependable operation while preserving the original driving experience of your classic Porsche.



Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.

91161814900
91161814600

The product you are viewing cross references to these numbers
DISPLAYING 1 to 2 (of 2 products)
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About Wiper Mechanism

Wiper mechanisms are essential components that ensure smooth, consistent windscreen wiping in your Porsche. Working in tandem with the wiper motor, the mechanism (also called the wiper linkage or transmission) converts the motor’s rotary motion into the sweeping movement of the wiper arms.

At Design911, we offer a complete range of genuine and high-quality aftermarket wiper mechanisms for all Porsche models - including 911, Boxster, Cayman, Cayenne, Macan, and Panamera. Each assembly is precision-engineered for perfect fitment, reliable motion, and long-lasting performance, whether you’re restoring a classic or maintaining a modern Porsche.

What Do Wiper Mechanisms Do?
The wiper mechanism connects the wiper motor to the wiper arms, transferring the motor’s torque through a system of linkages, joints, and pivots. This ensures the blades sweep across the windscreen at the correct angle and pressure, effectively clearing rain, dirt, and debris.

A properly functioning mechanism guarantees:

  • Smooth, synchronized wiper movement.
  • Correct blade positioning for maximum visibility.
  • Quiet, vibration-free operation.

Why Do Wiper Mechanisms Fail?
Over time, wiper mechanisms can suffer from mechanical wear or corrosion due to constant movement and exposure to the elements. Common failure causes include:

  • Worn joints or bushings: Causing excess play or uneven motion.
  • Corroded linkages: Leading to stiffness or total seizure.
  • Broken pivot arms or connecting rods: Often due to frozen wipers or excessive load.
  • Poor lubrication: Accelerating wear of metal components.

Signs of a failing wiper mechanism include uneven wiping, one arm not moving, noisy operation, or total failure of the wiper system.

Why Replace Faulty Wiper Mechanisms?
A damaged or worn wiper mechanism compromises safety by reducing visibility, especially in heavy rain. Replacing the mechanism ensures:

  • Reliable, smooth wiper function.
  • Clear and streak-free windscreen visibility.
  • Prevention of further damage to the wiper motor.
  • Compliance with MOT safety standards.

Design911 offers both genuine Porsche and premium aftermarket wiper mechanisms, ensuring perfect compatibility, precision movement, and OEM-level reliability. Every replacement part is designed to deliver durable performance and restore your Porsche’s wipers to factory operation.

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