Yes, a fuel pump relay can fail and disrupt required power supply to the fuel pump. The fuel pump relay works like a switch in which a small current from the ignition system controls a larger current that supplies the fuel pump. When a relay fails, the fuel pump does not get this power supply anymore, which could be manifested in a no-start condition, stalling, or just inconsistent fuel delivery. Most relays are rated to last about 100,000 miles or so, but wear, heat, and electrical resistance cause them to usually fail well before that time.
The most common causes of relay failure are contact wear. Inside each relay, metal contacts open and close to complete the circuit, and over time, those contacts degrade due to electrical arcing. That degradation builds a carbon deposit on the contacts, impeding conductivity. Vehicles that are driven more frequently at high loads may show more rapid wear on their relays because higher electrical demand accelerates the wear on the contacts. With respect to most mechanics, contact failure is associated more closely with relay malfunction in high-mileage vehicles.
Another culprit of relay failure is excessive heat. A fuel pump relay that is located in engine bays, or areas where the temperatures are high and could even run well over 200°F, will eventually suffer failure due to degradation from such heat internally. Sometimes, this temperature softens or distorts the relay plastic housing so that there is poor alignment of contacts. Such risks might be mitigated partially when there is a high-temperature environment by either shielding the relay or relocating it.
Poor wiring or a weak battery can also cause voltage problems that may ultimately make the relay fail. If the voltage severely drops, particularly below 12 volts, the relay might not be able to keep turning the fuel pump on. In older vehicles, corroded wiring can raise resistance and hence make the relay work harder until it fails. The fuel pump relay should be fed with stable voltage for reliable fuel delivery to be maintained.
As one automotive expert, Lee Iacocca once observed, “You can have brilliant ideas, but if you can’t get them across, your ideas won’t get you anywhere.” What is needed in place is a functioning Fuel Pump relay, in case one wants a reliable fuel system. For reliable replacement options and further information, please visit Fuel Pump.