How do you test the fuel pump relay - Mercedes 190e?

To test the fuel pump relay in a Mercedes 190E, first locate the relay in the fuse box. Use a multimeter to check for continuity by connecting the probes to the relay terminals; it should show continuity when energized. Alternatively, you can swap the relay with a similar one in the box to see if the fuel pump operates. If there's still no fuel delivery, the issue may lie elsewhere in the fuel system.