1. Relay: The fuel pump is usually controlled by a relay. This is the most common culprit.
* Location: Find the fuel pump relay in the underhood fuse box or interior fuse panel (consult your owner's manual). It's often labeled "FUEL PUMP" or with a similar designation.
* Check: Visually inspect the relay for any signs of damage (burnt contacts, etc.). You can swap it with a relay of the same amperage rating from a different circuit (like the horn relay, if it's a similar type) to see if that solves the problem. A clicking sound when you turn the ignition on usually indicates the relay is working, but a faulty relay might not click reliably.
2. Fuses: Check the fuses related to the fuel pump in both the underhood and interior fuse boxes. These might be labeled "FUEL PUMP" or something similar, but could also be a part of a larger circuit. Look for blown fuses (a broken filament inside).
3. Wiring: Problems with the wiring harness can interrupt power.
* Visual Inspection: Carefully examine the wires leading to the fuel pump relay and the fuel pump itself. Look for any signs of damage, such as chafing, cuts, or corrosion.
* Continuity Test: Use a multimeter to check for continuity in the wires. This requires some electrical knowledge and proper safety precautions.
4. Inertia Switch: Some vehicles have an inertia switch that cuts power to the fuel pump in the event of a collision. It's usually located under the dash or in the engine compartment. Check to see if it's tripped and needs to be reset (usually a button to push).
5. Fuel Pump Wiring Connector: Check the connector at the fuel pump itself. Look for corrosion, loose connections, or damaged pins.
6. PCM (Powertrain Control Module): While less common, a faulty PCM can prevent power from reaching the fuel pump. This is usually diagnosed with an OBD-II code reader. A mechanic will need to diagnose this.
7. Ignition Switch: A failing ignition switch can interrupt power to various circuits, including the fuel pump.
8. Security System: If the vehicle has an aftermarket or factory security system, it may be preventing the fuel pump from receiving power.
Troubleshooting Steps:
1. Start with the easiest checks: Fuses and the relay.
2. Visual inspection: Check all wires and connectors for damage.
3. Use a multimeter (if you have the knowledge): Test for voltage at the fuel pump relay, the fuel pump connector, and the wire leading to the fuel pump.
4. Check the inertia switch.
5. If all else fails, consult a mechanic: A faulty PCM, ignition switch, or more complex wiring issue requires specialized tools and knowledge.
Remember to disconnect the negative battery terminal before working on any electrical components. Safety first!
