1. Troubleshooting:
* Check the Fuel Level: The most obvious first step is to actually check your fuel level. If the car runs out of gas unexpectedly despite the gauge showing full, the gauge is definitely faulty. Fill your tank completely.
* Clean the Connections: Disconnecting and reconnecting the fuel level sending unit's electrical connector at the tank could resolve a simple corrosion issue. Use a wire brush to clean the terminals if necessary. This is the easiest and least expensive thing to try first. *Do this with the car OFF and the ignition key removed.*
* Check the Wiring Harness: Inspect the wiring harness running from the sending unit to the instrument cluster for any damage, breaks, or loose connections. Look for fraying, cuts, or corrosion. Pay close attention to the area where the harness exits the fuel tank.
* Check the Instrument Cluster (Advanced): While less likely, a problem within the instrument cluster itself could also cause this issue. This is more difficult to diagnose and often requires professional repair.
2. Repair/Replacement:
If cleaning connections and checking wiring doesn't solve the problem, the fuel level sending unit is the most likely culprit. This requires some mechanical work:
* Replacing the Fuel Level Sending Unit: This is the most common fix. This involves:
* Safety First: Work in a well-ventilated area. Fuel is flammable. Disconnect the negative battery terminal before starting any work.
* Access the Fuel Tank: This usually requires dropping the fuel tank. The procedure varies by model, but generally involves loosening fuel lines, disconnecting the electrical connector, and disconnecting any tank straps. Consult a repair manual specific to your 2000 Buick Century for the proper procedure.
* Remove the Old Sending Unit: This is typically secured with a retaining ring or clip.
* Install the New Sending Unit: Install the new sending unit, ensuring it's properly seated and the float moves freely.
* Reassemble Everything: Reinstall the fuel tank, reconnect fuel lines (paying close attention to proper tightening), and reconnect the electrical connector.
* Reconnect Battery: Reconnect the negative battery terminal.
Important Considerations:
* Repair Manual: A repair manual specific to your 2000 Buick Century is invaluable for this job. It will provide detailed instructions and diagrams. You can find these online or at auto parts stores.
* Safety: Working with fuel systems requires caution. If you're not comfortable working on your vehicle, it's best to take it to a qualified mechanic.
* Cost: Replacing the fuel sending unit involves labor costs if you have a mechanic do it, plus the cost of the part itself. It can be a moderately involved repair.
If the gauge still malfunctions after replacing the sending unit, then the issue could be with the wiring harness, the instrument cluster, or a less common electrical fault. At that point, seeking professional help is recommended.
