When a fuel pump relay fails, it breaks the relation between the fuel pump and the car electrical system. The engine stalling, difficulty starting, or failure to start up are some of the other frequent issues that may be developed with a faulty relay that would not allow the proper supply of electrical current to a fuel pump. According to NHTSA, “About 10% of all car breakdowns have something to do with the fuel system, and one of the usual suspects is electrical relay failure.
The typical fuel pump relay-one used by most vehicles in the last two decades-continues for about 100,000 miles. Factors like extreme temperature fluctuations or overuse, however, could significantly lower this life and wear the relay out sooner than later. In cold climates, for instance, the relay’s internal contacts can degenerate from increased electrical resistance, whereas in hot conditions, insulation on the wires can degrade, leading to a possible failure of performance.
To fix a faulty fuel pump relay, first locate the position of the relay. In most vehicles, it is located in the engine compartment and usually in the fuse box. For instance, in the 2010 Honda Accord, the relay is located in the under-hood fuse box, which is accessible by just removing the cover. Use a digital multimeter to check the continuity of the relay by testing the terminals. A lack of continuity indicates a faulty relay, and replacing it can restore proper function. Typically, a replacement fuel pump relay costs between $15 and $50 depending on the make and model, with labor costs adding another $50 to $100 if the replacement is done by a professional mechanic.
Also, check the wiring for any wear or corrosion. The Vehicle Service and Repair Industry Report says that about 25% of the electrical failures in fuel systems are due to faulty wiring or connections rather than the relay itself. If any corrosion or wear is found, cleaning the terminals or replacing the wiring could prevent future issues.
In the event of complete fuel pump failure due to a malfunctioning fuel pump relay, complete inspection of the vehicle might be required. According to an ARIA study, close to 30% of Fuel Pump failures are related to malfunctioning relays. When not treated, it increases the chances of much more expensive repairs. The cost for replacing both the relay and the pump may cost upwards of $500, depending on the model and labor involved.