The part number **2012341663** is a specialized automotive electronic component manufactured by **Mercedes-Benz**. It is a **Relay**, specifically used as a **Fuel Pump Relay** or an **Overload Protection Relay** depending on the specific chassis and engine configuration. --- ### 1. Component Specifications | Attribute | Details | | :--- | :--- | | **Manufacturer** | Mercedes-Benz (Genuine OEM) | | **Part Type** | Electrical Relay | | **Primary Function** | Fuel Pump Control / Voltage Protection | | **Voltage** | 12V DC | | **Connector Type** | Multi-pin Plug-in (Blade style) | --- ### 2. Functional Description This electronic part acts as a high-current switch. In older Mercedes models (such as the W124, W201, or R129), it serves critical roles in the engine management system: * **Fuel Pump Activation:** It completes the circuit to the fuel pump when the ignition is turned to "Start" and maintains the connection while the engine is running. * **Safety Cut-off:** It is designed to cut power to the fuel pump if the engine stalls or if no RPM signal is detected from the crankshaft sensor, preventing fire in the event of an accident. * **Engine Speed Limiter:** Some versions of this relay also act as a "Kickdown" relay or contain logic to limit the maximum RPM of the engine. --- ### 3. Common Failure Symptoms Because this is an older electromechanical part, it is prone to failure over time. Common signs of a faulty 2012341663 relay include: 1. **Crank, No Start:** The engine turns over but does not fire because the fuel pump is not receiving power. 2. **Intermittent Stalling:** The vehicle shuts off randomly while driving. 3. **Hard Starting:** The relay fails to prime the fuel system when the key is first turned. 4. **Noisy Fuel Pump:** Low voltage through a failing relay can cause the pump to strain. --- ### 4. Technical Identification When searching for a replacement or inspecting the part, look for the following characteristics: * **The Housing:** Usually a rectangular black or silver plastic/metal casing. * **The Pins:** Look for oxidation or "burnt" marks on the bottom pins, which indicates a poor connection or internal short. * **Internal Circuitry:** These relays often contain a small circuit board with solder joints. A common fix among enthusiasts is "re-soldering" cracked joints on the internal PCB. ---