Checking for fuel pump relay problems is generally carried out in a few main steps to find out whether the relay is leading to flawed fuel delivery. The first thing you need to do is locate your relay, which is normally situated in the fuse box beneath your hood or near the dashboard inside the car. Most relays are rated for 12 volts to match the vehicle’s electrical system and can be designed to last approximately around 100,000 miles. Consequently, when it finally reaches a point of premature failure, some of the symptoms that may be developed are fuel pump malfunction, stalling, and no-start.
It is possible to test the relay based on continuity by taking a multimeter reading. The multimeter should be set to read resistance in ohms by connecting the leads across the terminals of the relay. Normally, for a healthy and functioning relay, a specific resistance range will be given-usually from 50 to 120 ohms, depending on the specifications. A reading outside this might mean an internal fault, and hence the relay is to be replaced.
Another test is the “relay swap” test. Swap the suspected fuel pump relay out with another similar-type relay situated under the fuse box, often labeled for a secondary system like the headlights. If the fuel pump now works after the switch, then the relay is likely at fault. Quick, and requiring no special tools, this method is also favored by technicians since it can be extremely handy when trying to diagnose no-start situations on high-mileage vehicles.
It also helps in identifying the problems in the relay by listening to a clicking sound when the ignition is turned to the “on” position. The click goes to signalize that the current is allowed to reach the Fuel Pump due to the activation of the relay. If the click sound is not heard, the relay might not get power or has completely failed. In such scenarios, further troubleshooting of the wiring along with the fuse is required to eliminate other electrical issues which might appear as a relay failure.
Also, unplanned breakdowns can be avoided by replacing the fuel pump relay at regular periods, usually every 100,000 miles, as part of routine maintenance. If you need reliable Fuel Pump and relay components, visit for more information.