How Do You Check a Fuel Pump Relay?

To check a fuel pump relay, locate the pump relay and remove it, identify the two control and power circuit terminals, and then test the resistance between the terminals. You need an ohmmeter and jumper wires for this process.

Open the hood of the vehicle, and unlock the security latch with your fingers to gain full entry to the engine area. The pump relay is usually on the fuel panel or close to it. However, other vehicles have the relay on the passenger or driver side, or under the dashboard. Unplug the pump relay to remove it, taking care not to break the lock tabs.

Check the printed diagram on the relay's casing or the relay?s mounting base to identify two control and two power circuit terminals, where two thin wires and two thick wires connect to the relay. Use an ohmmeter, which should be on the lowest setting, to test the resistance between the terminals. Replace the relay if the reading is not infinite resistance. However, when testing the power terminals, replace the relay if the reading is infinite resistance.

Connect the end of a fused jumper wire to the positive terminal of the vehicle?s battery and the other end to the control circuits on the relay. Fix one end of the regular jumper to the other control terminal, and hold the other end to the engine block, which should produce a clicking sound. Replace the relay if you do not hear any clicking sound.