Mercedes-Benz 300SD Fuel Pump Relay Replacement at your home or office.

What is the Fuel Pump Relay all about?

Every time you turn on the ignition of your car, you activate the fuel pump relay. This device sends an electric current to the fuel pump. Upon receiving this current, the fuel pump sends gasoline to the engine and the car starts running. While the fuel pump is active as long as the car engine is running, the fuel pump relay works only at startup and when you turn off the ignition. As long as the car is running, the fuel pump runs on the power it receives from the oil pressure sending unit or any other such power source.

The fuel pump relay is also called the relay switch and its functions are similar to those of the automotive fuse. Controlled by the engine control module, the fuel pump relay controls the current sent to the fuel pump. This device is a black plastic component, set in a small box with a wiring harness attached to its underside. Its sprockets attach to the engine assembly. Depending on the make of the car, you will find the fuel pump relay under the hood or under the dashboard, near the steering wheel of the car.