Here's a breakdown of how to trace the wire, combining several techniques:
1. Consult a Wiring Diagram:
* This is the MOST important step. A factory wiring diagram for your specific year and model Oldsmobile 98 is crucial. You can often find these online through sites specializing in automotive repair manuals (like Haynes or Chilton) or through online forums dedicated to Oldsmobiles. The diagram will show the exact path of the fuel pump wire from the fuse box/relay to the pump.
2. Tracing from the Fuel Pump (Less Safe, More Difficult):
* Disconnect the battery negative terminal.
* Locate the fuel pump. It's usually in the fuel tank, requiring access from under the car.
* Carefully disconnect the electrical connector from the fuel pump.
* Using a multimeter or test light, carefully check for continuity between the fuel pump connector and the suspected wire leading toward the engine compartment. Be extremely careful not to short anything. This method helps identify the wire at the pump end, then you can trace it back.
3. Tracing from the Fuse Panel/Relay (Safer, More Common):
* Disconnect the battery negative terminal.
* Locate the fuse and relay related to the fuel pump in the fuse panel (your wiring diagram will tell you which one it is).
* With the multimeter or test light, test for power at the fuse and relay. You've already confirmed power here, but this is a double-check.
* Carefully start tracing the wires leaving the relay. This is often easier said than done, as many wires are bundled together. You'll likely need to use the wiring diagram to visually identify the correct wire color and gauge.
* Use your multimeter to test for continuity between the wire you're tracing and the fuel pump connector (remember to disconnect the fuel pump connector first!). This confirms you're following the correct wire.
4. Using a Wire Tracer (Professional Approach):
* A professional-grade wire tracer uses a signal injector and receiver. You inject a signal into the wire at the fuse box/relay and trace it using the receiver. This is less time-consuming than manual tracing. These tools are often available at auto parts stores or for rent.
Important Considerations:
* Wire Colors: The wiring diagram will show the wire color. However, over time, wire colors can fade. Don't rely solely on color; use your multimeter for confirmation.
* Multiple Wires: The fuel pump wire may be bundled with other wires. Careful and methodical tracing is essential.
* Safety First: Gasoline is highly flammable. Work in a well-ventilated area. Avoid sparks and open flames. Always disconnect the negative battery terminal before starting.
If you're not comfortable working with automotive electrical systems, it's best to take your car to a qualified mechanic. Improperly working on the fuel system can lead to fire or injury. The time and effort involved in tracing wires can be significant. A wiring diagram is your best tool and will greatly speed up the process.
