A liquid level indicating device such as the fuel gauge 10 in a motor vehicle is of the type which does not return to zero when the ignition is switched off. In order to prevent false readings arising when the fuel in the tank sloshes about, a tilt switch (22) is provided in series with the ignition switch (24) to disconnect the power to the fuel gauge (10), which then continues to register the previous reading, if the motion or attitude of the vehicle changes. The tilt switch (22) will close again once the vehicle returns to its normal operating state, and power will be restored to the gauge (10) which then reverts to direct reading of the signal from a sender unit (28) in the fuel tank.