Possible Causes:
* Faulty Fuel Pump: The most common culprit. A failing fuel pump motor can draw significantly more current than normal, leading to a blown fuse. This is especially likely if the pump is making unusual noises (whining, grinding) or the car is struggling to start.
* Wiring Problems:
* Chafed or Damaged Wires: Wires in the fuel pump circuit (running from the fuse box to the fuel tank) can become chafed against the chassis, rubbing on other components, or damaged by rodents. This creates a short circuit. Inspect the entire wiring harness carefully, paying close attention to areas where the wires are routed near moving parts or sharp edges.
* Corrosion: Corrosion on wire connectors can increase resistance and lead to excessive current draw. Check all connectors for corrosion and clean them thoroughly.
* Short to Ground: A wire may be shorted directly to the chassis (ground). This is a common cause of blown fuses.
* Faulty Fuel Pump Relay (if applicable): Some systems use a relay to control the fuel pump. A stuck-closed relay will constantly power the pump, even when it shouldn't, leading to a blown fuse.
* Fuel Pump Inertia Switch (if applicable): Some vehicles have an inertia switch to cut power to the fuel pump in a collision. If this switch is stuck in the "off" position and then manually reset, it could trigger a surge of power and blow the fuse.
* Low Fuel Level (less likely): An extremely low fuel level *might* cause the pump to work harder, but this is less likely to blow a fuse unless there's another underlying problem.
* Incorrect Fuse: Double-check that you're using a 15-amp fuse of the correct type (slow-blow/automotive type). Using a higher amperage fuse is dangerous and will not solve the problem.
Troubleshooting Steps:
1. Visual Inspection: Carefully inspect all wiring related to the fuel pump. Look for any signs of damage, chafing, corrosion, or melted insulation.
2. Check the Fuel Pump Relay (if applicable): Locate the fuel pump relay (consult your owner's manual or online resources for its location), and check if it's clicking properly. If you suspect the relay, try replacing it.
3. Check the Fuel Pump Inertia Switch (if applicable): Locate the inertia switch (usually near the passenger side footwell or under the dash). Try resetting it.
4. Test the Fuel Pump (advanced): This requires a multimeter and some electrical knowledge. You can measure the resistance of the fuel pump itself and check for shorts or continuity problems in the wiring. Caution: This involves working with potentially hazardous fuel system components. If you are not comfortable with this, take your vehicle to a mechanic.
5. Professional Diagnosis: If you can't find the problem after careful inspection and testing, take your vehicle to a qualified mechanic. They have specialized tools and expertise to diagnose the issue accurately.
Important Safety Note: Work on the fuel system involves dealing with flammable fuel. Take appropriate precautions to avoid sparks or open flames. Disconnect the negative battery terminal before working on the electrical system.
