1. Check the Fuel Gauge:
* Erratic Gauge: A fluctuating or inaccurate fuel gauge *strongly* suggests a bad fuel sending unit. The gauge is directly connected to the sending unit; a faulty unit sends incorrect resistance signals.
* Gauge Reads Empty Even with Fuel: This also points to a faulty sending unit.
2. Listen for the Fuel Pump:
* Turn the Key to "On" (without starting): You should hear a brief humming sound from the fuel pump. This sound indicates the pump is receiving power and priming. If you don't hear it, the pump may be faulty or not receiving power.
* Note: The sound might be subtle, so listen carefully. The pump is usually located near the fuel tank.
3. Check Fuel Pressure (Most Crucial):
* This requires a fuel pressure gauge. This is the most definitive test. You need to connect the gauge to the fuel rail (usually on the intake manifold). Consult your vehicle's repair manual for the correct port and specifications.
* Turn the Key to "On": The pressure should build up to the specified level in your manual (typically around 30-40 PSI for this vehicle, but check your manual). If it doesn't build, or it builds slowly, it strongly indicates a fuel pump problem.
* Run the Engine: The pressure should remain steady while the engine is running. A fluctuating pressure suggests a pump or pressure regulator issue.
4. Inspect the Fuel Filter:
* A clogged fuel filter can mimic the symptoms of a failing fuel pump. Replace the fuel filter as part of routine maintenance to ensure proper fuel flow.
5. Check for Power to the Fuel Pump:
* This requires a multimeter. You need to access the fuel pump wiring and check for power at the pump's connector with the key in the "On" position. A lack of power means the problem is not the pump itself, but rather the wiring, relay, or fuel pump inertia switch. The inertia switch is a safety device that cuts power to the pump in a collision; it's usually located under the dash or in the engine bay.
6. Visual Inspection (Less Reliable):
* Inspect wiring harnesses for damage to the fuel pump wiring. Damaged or corroded wires can prevent the pump from receiving power.
* Check the fuel pump relay (if applicable). Swapping it with a known good relay from a different circuit (with caution!) might help determine if it's at fault.
Important Considerations:
* Safety First: Always disconnect the negative battery terminal before working around fuel components. Fuel is highly flammable.
* Repair Manual: A repair manual specific to your 1995 Ford Explorer is invaluable. It will provide detailed diagrams, specifications, and troubleshooting steps.
* Professional Help: If you are not comfortable performing these tests, take your Explorer to a qualified mechanic. Replacing the fuel pump and sending unit can be labor-intensive.
By systematically checking these points, you can better pinpoint whether your issue lies with the fuel pump or the fuel sending unit on your 1995 Ford Explorer. The fuel pressure test is the most definitive.
