Description
Mercedes W118 W177 W205 W907 Brake Light Switch Button Electrical is an original component from the Switches, control elements and ignition locks group, designed for precise control of the brake light signal in Mercedes vehicles. Maintaining the efficiency of this sensor is crucial for driving safety, proper operation of the braking system, and interaction with driver assistance systems.
Specifications and technical data
- SKU: A0005452812-2
- Mark: Mercedes (Genuine OE)
- Condition: Used
- OEM Part Number: A0005452812
- Substitutable numbers: A0005452812, A 000 545 28 12
- Category: Switches & Controls
Function and application of the brake light switch
The brake light switch is responsible for generating an electrical signal when the brake pedal is pressed, which activates the rear brake lights and informs the associated control modules that braking has begun. In modern Mercedes W118, W177, W205, and W907 series, the signal from this component can also be used by electronic stability control systems, safety assistants, and transmission control units.
A properly functioning sensor ensures:
- immediate activation of brake lights for vehicles behind you,
- consistent input signal for electronic safety systems,
- stable cooperation with the braking system and vehicle control.
Benefits of using an original Mercedes component
Choosing a brake light switch dedicated to specific Mercedes generations translates into high installation compatibility and predictable performance in the factory electrical system. The original component from the Switches, control elements and ignition locks group has been designed for:
- fitment to the wiring harness and connectors used in the given body platform,
- cooperation with factory control units without the need for adaptation,
- maintaining operating parameters consistent with the vehicle manufacturer’s specifications.
This reduces the risk of diagnostic errors, fault messages on the dashboard, and problems with brake light activation in critical road situations.
Installation and operational characteristics
The brake light switch in the discussed Mercedes models is a component that works directly with the brake pedal mechanism. Its design provides a specific operating range, appropriate sensitivity, and signal stability during long-term use. When replacing, it is important to maintain the correct mounting position and proper seating in the bracket to:
- ensure a repeatable brake light activation point,
- avoid delays in reaction to pedal depression,
- prevent accidental brake light illumination when the brake is not in use.
Using a component intended for the specific vehicle platform facilitates service, shortens installation time, and reduces the risk of needing additional adjustments.
Selection and quality control of the used sensor
The presented sensor comes from our used parts offer, which allows for economical service while maintaining the original manufacturer’s specifications. In practice, this means the ability to restore full functionality of the brake light system without the need to resort to replacements with uncertain parameters. Before installation, it is recommended to verify proper operation in the vehicle or on a diagnostic stand, with particular attention to:
- the moment of signal activation and deactivation,
- stability of operation during repeated brake pedal depression,
- absence of circuit breaks and proper electrical contact.
To better plan the service of the braking system using parts from the secondary market, it is worth using the advice contained in the article: Braking system second-hand: how to safely choose discs, calipers, and ABS?.
Service expansion within control and signaling
If you are planning a comprehensive repair or modernization of the control and signaling zone in your Mercedes and need other elements from the same group, such as combination switches, steering column control elements, or ignition lock components, check the available parts in the Mercedes Switches, control elements and ignition locks category.






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