Yesterday, the fuel indicator light was on. I filled it up with 10 liters, and the gauge moved visibly.
Today, the light was on again. I fueled it up for 5 liters. No movement. Then I fueled it up for 5 liters more. No movement. The gauge is still at the same point as it was before both fillings. Light is still on.
Why does this happen? It's a Renault Master van.
(which I am borrowing on a daily basis, and need to fuel it for only the amount I drive, which typically is in the 5-10 liter range).