Mercedes W168 W169 W245 Blue Relay 4-Pin Tyco A0025422519

Mercedes W168 W169 W245 Blue Relay 4-Pin Tyco is a component from the Relays category, designed for the starting system in Mercedes A-Class (W169) and B-Class (W245) vehicles. This used, original component ensures proper control of the starter circuit, which translates into stable engine starting and correct cooperation with the vehicle's electrical system. The characteristic blue housing facilitates quick identification of the component in the fuse and relay box.

Specifications and technical data

• SKU: A0025422519
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A0025422519
• Substitutable numbers: A0025422519, A 0025422519, A 002 542 25 19
• Color: Blue
• Category: Relays

Purpose and function in the starting system

The Mercedes W168 W169 W245 Blue Relay 4-Pin Tyco is responsible for engaging the high-current starter circuit based on a control signal from the low-current system. Thanks to this, the ignition switch or electronic module is not burdened with high starting current, and the entire system operates under controlled electrical conditions.

In practice, this means that a properly functioning relay:

• stably transmits the start signal to the starter,
• reduces the risk of voltage drops in the system,
• supports proper cooperation with the vehicle's factory security systems.

Construction and functional features

The relay has been designed as a component installed in the factory Mercedes relay box, with a matched pin layout and housing adapted to operating conditions in the engine compartment or inside the vehicle. The blue color of the housing makes it easy for service technicians and users to quickly locate the correct component during diagnostics or replacement.

As a part from the Relays group, the component works with other elements of the electrical system, such as fuses, other control relays, and electronic modules, creating a coherent and predictable power supply and starter control system.

Benefits of using an original Mercedes relay

Using an original starter relay in W169 and W245 models allows you to maintain the factory operating parameters of the starting system. This solution is particularly beneficial when you care about:

• maintaining compatibility with the vehicle's electrical system,
• reducing the risk of engine starting problems,
• maintaining consistency with other OEM components in the car.

A used OEM component is often chosen as a reasonable compromise between cost and quality, especially for vehicles used on a daily basis, where reliability and predictable behavior of the starting system are important.

Selection and application in service practice

When selecting a starter relay for a Mercedes A-Class or B-Class, it is crucial to match it to the specific vehicle generation and electrical system configuration. Proper selection of a component from the Relays category allows you to avoid problems with improper starter engagement, intermittent operation, or errors in onboard systems.

In service practice, the starter relay is most often replaced when symptoms appear such as sporadic lack of response to a start attempt, the need to turn the key multiple times, or unstable starter operation despite a functional battery and main system.

If you are planning a comprehensive repair or upgrade of the electrical system area in your Mercedes and need other components from the same group, such as fan control relays, fuel pump relays, or light relays, check the available parts in the Mercedes Relays category.

Additional technical and operational support

When working with the vehicle's electrical system – especially in the area of starting, power supply, and comfort systems – it is worth paying attention to the condition of other components, such as connectors, wiring harnesses, or control modules. Good practice is periodic inspection of the system to reduce the risk of failures resulting from contact corrosion or electrical overloads.

If you want to expand your knowledge on selecting used OEM components and the principles of maintaining systems responsible for comfort and proper vehicle operation, the guide article Air conditioning and heating – part selection and maintenance for year-round comfort, which discusses practical service procedures and tips regarding operation, may be helpful.