Mercedes W204 Anti-Theft Alarm Siren Horn Signal Bracket Holder A2045456740

Mercedes W204 Anti-Theft Alarm Siren Horn Signal Bracket Holder is a component from the Horns category, responsible for generating a clear acoustic signal in the vehicle's factory security system. This solution is designed for users who expect a proven, original-compliant construction and stable operation of the alarm system in Mercedes vehicles.

Specifications and technical data

• SKU: A2045456740-1
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A2045456740
• Substitutable numbers: A2045456740, A 204 545 67 40, KZ
• Category: Horns

Purpose and function in the vehicle

The alarm siren used in W204 series models is responsible for acoustic notification of a vehicle zone breach, working in conjunction with the factory alarm system and central locking. This element, as part of the Horns group, generates a characteristic, loud sound that increases parking security and facilitates vehicle location in emergency situations.

This type of solution is designed for compatibility with Mercedes vehicle electronics, which allows for maintaining proper communication with control modules and minimizes the risk of installation errors.

Construction and performance parameters

The alarm siren in this configuration is based on a compact, durable housing, adapted for operation in the engine compartment or other areas of the bodywork exposed to external conditions. The design provides:

• a dedicated electrical connector matched to the installation in the Mercedes W204,
• a housing protecting against moisture and road debris,
• acoustic characteristics adapted to the requirements of the factory alarm system.

Thanks to this, the sound signal remains clear, and the system operation is stable under typical vehicle operating conditions.

Condition of the item and benefits of choosing a used part

The offered alarm siren is a used component, which allows for an economical replacement of a damaged part while maintaining compliance with the manufacturer's original specifications. In practice, this means the ability to restore full functionality of the alarm system without the need to invest in a new component.

Choosing an original, used element from this group is particularly beneficial for service repairs, where fitment to the electrical installation, proper cooperation with control modules, and predictable behavior in daily operation are important.

Selection and practical application

Before installation, it is recommended to verify the compatibility of the siren with the specific vehicle equipment version, which is facilitated by identification using data such as SKU or OEM part number visible in the technical specifications section. This helps avoid compatibility issues and ensures proper cooperation with the existing alarm system.

This element will work well both for standard replacement of a damaged siren and for restoring the security system's efficiency after bodywork repairs or interference with the electrical installation.

If you are planning a comprehensive repair or upgrade of the area responsible for acoustic signaling in your Mercedes and need other elements from the same group, such as horns, additional acoustic modules, or related alarm components, check the available parts in the Mercedes Horns category.

Technical support and knowledge for the driver

When working with the vehicle's electrical installation, including the alarm system, it is worth paying attention to symptoms such as unstable operation of receivers, voltage drops, or flashing warning lights. For drivers interested in a broader context of electrical component operation, a practical guide material may be useful – more information can be found in the article When is it worth replacing an alternator with a used one: a practical guide for drivers.