Wire a fuel gauge by first disconnecting the old dysfunctional unit to replace it with a new one. Obtain 12-volt power from the fuse box using a standard wire, and connect it to the positive terminal of the fuel gauge. Next, connect a wire from the float on the fuel tank to the negative terminal of the fuel gauge.
When wiring a fuel gauge, it is wise to have a full tank in order to monitor the installation correctly. Next, gather all the necessary tools and equipment together. Be careful not to use power tools around the fuel tank, as it can lead to combustion or explosion.
The float is usually made of fiberglass and connected to a resistor. If wired wrongly, there will be some inaccuracies on the fuel gauge reading as compared to the actual volume of fuel in the car’s tank. For example, the needle on the gauge may remain in the "full" position even after travelling a considerably long distance. On the other hand, the needle may remain on the "empty" position even after the car has been fueled with a considerable volume. The shape of the fuel tank can also cause these errors, as they may be shapelessly designed to fit in the frame of the car.