Main / ECU Relay - White - E30 E36 E39 E38 X5

This is a Genuine BMW main relay for a variety of BMW models. The main relay powers vital systems in the car when the key is turned to the Start position. Things like the ECU and fuel pump require power from the main relay before they can work. The main relay is constantly powered so checking for power is easy with a test light. It should also make a 'click' sound when the ignition switch is turned. Note: relays look similar but can perform different functions, and electrical parts are non-returnable, so make sure you confirm this is the relay you need.