What Causes Fuel Pump Relay Failures?

Fuel pump relays may fail due to various reasons such as electrical surges, overheating, and worn-out contacts inside the relay. The fuel pump relay is simply an on-off switch that controls the electrical current going to the fuel pump. Since it operates in a similar manner to other switches, electrical contacts wear out over time due to arcing, or small electric sparks, which occur every time the relay opens or closes. This can cause carbon buildup on the contacts and create resistance that impairs the relay’s ability to easily transmit power. It is a fact that relay contacts start to wear out after 100,000 miles, which is the reason they are more likely to fail in older vehicles.
Another cause of relay failure involves overheating. The fuel pump relay operates under high temperatures and is usually designed to be in the fuse box of a vehicle inside the engine bay. Once the temperatures exceed 140°F, some components of the relay may warp or deteriorate since its efficiency lowers along with its lifespan. The consistent exposure to high heat causes material fatigue, which results in the failure of the relay to supply steady voltage to the fuel pump. High-temperature-resistant relays are thus recommended for performance applications where the engine bay sees a lot more heat.

Electrical surges can be another cause of fuel pump relay failure. Surges of voltage from either the alternator or the battery can overload the circuitry inside the relay and may burn out the coils inside. This is often the case when the battery or alternator is malfunctioning, causing spikes to burn the relay. Professionals recommend periodic diagnosis of the electrical system in vehicles regarding the output of batteries or alternators to avoid damage to relays without any genuine reason.

Further, fuel pump relays have also been influenced by moisture and corrosion in some regions that have high humidity or where the vehicle is prone to water exposure. The moisture gains ways into the relay housing, resulting in corrosion at the contacts of metals, hence poor electrical conduction. Sometimes, an intermittent operation or complete failure may be realized. The protective relay housing or anti-corrosion treatments enables the long lives of such relays in those environments.

What are the common causes of the Fuel Pump relay failure? The answers are electrical wear, overheating, surges, and corrosion-factors especially applicable to older or high-performance vehicles. Regular checks on the electrical system, coupled with protective measures, can minimize the possibility of relay failure for reliable fuel pump operation.

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