Mercedes W166 Front Seat Belt Upper Left N/S Side Pretensioner A1668603586

The Mercedes W166 Front Left Seatbelt Pretensioner is an original safety system component designed for installation on the driver's or front passenger's side (left side). It ensures proper cooperation with the factory seatbelt, supporting the correct operation of the passenger protection system in the W166 body.

Specifications and technical data

• SKU: A1668603586
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A1668603586
• Substitutable numbers: A1668603586, A 166 860 35 86
• Location on the vehicle: Front, Left
• Category: Seat Belts & Parts

Purpose and Function in the Vehicle

The presented front seatbelt upper mount pretensioner operates in the front-left area of the vehicle. It is responsible for the controlled tightening of the belt upon activation of the safety system, which helps to limit the movement of the driver's or passenger's body relative to the seat.

This component is part of the seatbelts and parts category, therefore its correct operation directly impacts the effectiveness of the entire safety system in the Mercedes SUV on the W166 platform.

Benefits of Using an Original Pretensioner

Using a factory pretensioner in the Mercedes W166 allows for:

• System Compatibility – the component is designed to work with the vehicle's factory control units and sensors.
• Correct Belt Routing Geometry – the upper mount on the pillar ensures the correct path of the belt relative to the shoulder and chest.
• Stable Structural Mounting – precisely matched mounting points facilitate correct bolting to the body without modifications.
• Predictable Behavior During a Collision – the pretensioner works with other system components, supporting predictable vehicle behavior in emergency situations.

Product Characteristics and Installation

The pretensioner is designed for installation on the front left side of the cabin, in the area of the upper seatbelt mount. The construction is prepared for operation within the factory Mercedes system, which facilitates a plug-and-play installation in the appropriate W166 model, while adhering to manufacturer procedures.

As a component from the seatbelts and parts group, the pretensioner should be installed by a qualified service center, following safety regulations for pyrotechnic and electronic systems. Correct installation is crucial for the effective operation of the entire system.

Condition and Origin

The offered pretensioner is an original Mercedes component from the aftermarket. This solution allows for maintaining factory fit and performance characteristics while reducing costs compared to a new part from an authorized dealer.

If you want to better understand why a used original part can be a beneficial choice, it's worth reading the practical tips in the article 5 Reasons Why a Used OEM Part is a Better Choice Than an Aftermarket Replacement.

How to Reduce Repair Time and Select the Right Mercedes Seatbelts and Parts

When replacing components such as a front seatbelt pretensioner, quick availability of the correct component is key. Used OEM parts can often significantly reduce vehicle downtime in the service center – you can find more on this topic in the guide Immediate Availability of Car Parts vs. Repair Time – How Used OEM Parts Reduce Workshop Stays?.

If you are looking for other Mercedes seatbelts and parts tailored to your model, check out our dedicated offer: Mercedes Seatbelts and Parts. This will make it easier to assemble the entire safety system in accordance with manufacturer requirements.