BMW Relay (Si121 09-89) - Genuine BMW 13631725654

Product Information

BMW Relays diagram for 750iL

A fuel pump relay is an electrical component that controls the power sent to the fuel pump. It’s usually located in the fuse box and plays a critical role in starting the fuel pump, which then supplies fuel to the engine. The relay ensures that the pump receives power only when needed, such as when the ignition is on, allowing the engine to start and run efficiently.

• Engine Won’t Start: One of the most common symptoms of a failed fuel pump relay is a no-start condition. If the relay isn’t sending power to the fuel pump, the engine won’t receive the fuel it needs to start
• Intermittent Stalling: If the fuel pump relay is failing or losing connection intermittently, the engine may stall while driving, as the fuel pump will lose power momentarily. This is especially common if the relay is overheating or has a loose internal connection
• Rough Idle or Hesitation: A failing relay may cause irregular fuel delivery, leading to rough idling or hesitation during acceleration, as the engine isn’t receiving a steady fuel supply

About Genuine BMW

The original parts used by BMW to build your car are available as replacement parts under the “Genuine BMW” brand. When ordering a Genuine BMW part you are guaranteed to get the same part that you would pick up from your local dealerships part department. Genuine BMW parts have been built to BMW’s stringent standards and are the same quality of the original parts used to build your Ultimate Driving Machine.

You may not realize this, but the parts that make up your BMW are not necessarily manufactured by BMW. No cause for concern, as BMW designs the part, hires a manufacturer, and ensures its quality to you. In fact, many of these manufacturers have been making parts for BMW for decades. In our industry these manufacturers are called OEM (Original Equipment Manufacturers), and these are often brands you recognize, including Lemforder, ZF, Sachs, Bosch, Valeo, Zimmermann, Siemens VDO, Corteco, and more. Don’t be surprised to open that Genuine BMW parts box and find an OEM branded part inside, simply with the addition of a BMW logo.

Be sure to keep an eye out for OE tags on our product pages to quickly identify parts coming direct from OE manufacturers. That extra bit of insight could save you some serious money while shopping! Refer to our OE Academy for further information regarding the OE/OEM tags throughout the site.