1. Verify Power and Ground
* At the Pump:
* Power: With the key on, check for power at the pump's electrical connector. Use a test light or multimeter to verify voltage (should be battery voltage).
* Ground: Look for a good ground connection at the pump. Make sure the ground wire is secure and not corroded.
* At the Fuel Pump Relay:
* Location: Consult your owner's manual or online resources to find the fuel pump relay location.
* Power and Ground: Check the relay for power and ground (usually on the relay socket) with the key on.
2. Check the Fuel Pump Relay
* Continuity: Use a multimeter to test the relay's internal contacts for continuity when it should be energized (check your owner's manual for the specific relay pinouts).
* Swap: If you have access to another relay (or a spare from a known good vehicle), swap the relays to see if it resolves the issue.
3. Inspect the Wiring
* Visual Inspection: Examine the wiring leading to the fuel pump for:
* Corrosion: Look for any green corrosion on the wires or connectors.
* Damaged Insulation: Check for frayed or damaged insulation.
* Loose Connections: Inspect the connections for loose or broken terminals.
* Continuity Test: Use a multimeter to check for continuity through the entire wiring path. If you find an open circuit, you've located your problem.
4. Check the Fuel Pump Control Module (PCM)
* PCM Location: This will be located under the dash or in the engine bay.
* Check for Codes: Use an OBD-II scanner to retrieve any diagnostic trouble codes related to the fuel system. This might point to a faulty PCM or other related component.
* PCM Output Test: (This step requires advanced diagnostic equipment) Check if the PCM is sending the signal to the fuel pump.
5. Additional Considerations:
* Safety: Always disconnect the battery before working on electrical components.
* Repairing Wiring: If you find a wiring fault, replace the damaged section or repair it using proper techniques and heat shrink tubing.
* Professional Assistance: If you're not comfortable with electrical diagnostics, it's best to seek help from a qualified mechanic.
Remember: This guide provides a general approach. Specific testing procedures and locations may vary depending on your vehicle's year and model. Always consult your vehicle's repair manual or a reputable online resource for detailed information specific to your Pontiac Grand Am 2000.
