Fuel Gauge: Description and Operation

Fuel Gauge Circuit Operation
When the fuel tank level is low, the resistance of the fuel gauge sender is approximately 245 ohms. As the fuel level increases, the resistance of the sender decreases, causing the gauge to register the change. When the fuel tank is full, the resistance of the sender is approximately 19 ohms. When the fuel gauge sender's resistance falls below approximately 25 ohms (6 liters/1.5 US gallons), the fuel warning light will illuminate to warn the driver.