Mercedes-Benz SL500 fuel gauge inaccurate, runs out of fuel at 1/4 tank on Mercedes-Benz SL500

Some Mercedes-Benz SL500 owners report experiencing issues with an inaccurate fuel gauge, leading to running out of fuel at a quarter tank. This problem may be caused by a faulty sending unit in the tank, corroded or loose wiring connections, or a malfunctioning actuator on the dashboard gauge. To troubleshoot, some owners suggest testing the fuel gauge with different value resistors to see if it responds correctly. Additionally, backprobing the signal wire in the connector and grounding it can help determine if the gauge will move to full. Owners should also be cautious when swapping wiring connections, as doing so with a connected sender may prevent the gauge from functioning properly until the tank is empty. Addressing these issues promptly can help prevent unexpected fuel shortages.