Can you test a relay. If so how. How can i identify my Fuel Pump relay from the one beside it?

 

Sure you can test it. All you need is an ohmmeter, a voltage source, and some spare wire.

The relay should have 5 terminals, numbered 85, 86, 87, 87A, and 30. 85 to 86 is the coil side. With the meter, check across the coil. Obviously an open circuit is bad. You should see some resistance, sometimes as high as 100 ohms. 87, 87A, and 30 are the switched terminals. You should see continuity from 87A to 30 with no current across the coil. With current, it should show continuity across 87 to 30.

Apply voltage to 85, and ground 86. The relay should click, and should show continuity across 87 to 30. If it doesn't click or switch, the relay is bad. Any resistance higher than around 10 ohms across the switched side and it should be replaced, even though it may still function.

Of course, the easiest way to test a relay is to swap it with a good known unit