You might be thinking of one of these things:
* Trip Odometer Reset: This button resets the trip odometer, which tracks mileage since you last reset it. This is useful for calculating fuel economy. This button is usually located on the instrument cluster, near the speedometer.
* Fuel gauge inaccuracy: If your fuel gauge is reading incorrectly, there's no button to fix it. The problem could be a faulty fuel level sensor, wiring issue, or even just a simple glitch. You'll likely need to have a mechanic diagnose and repair this.
* Check Engine Light: If you're having fuel-related issues, a "Check Engine" light may illuminate. This doesn't have a reset button either; the light indicates a problem that needs diagnosis and repair. A code reader can help determine the issue.
To clarify what you're trying to do, please specify what you're hoping to achieve by pressing a "fuel reset button."