idiot light

An indicator light or illuminated signal, usually colored red, yellow, or orange, on a vehicle dashboard intended to convey a condition of which the driver should be aware. Most frequently, it indicates a system malfunction or a potentially dangerous condition (e.g., low oil pressure, high coolant temperature). It may be a word or words ("Charge"; "Check Engine") or a symbol which may or may not be readily identifiable.

The derisive term comes from the fact that such lights typically take the place of a gauge, meter or other indicator that can provide more substantive and detailed information. The binary (on/off) nature of the light is considered inferior to an indicator which provides data on the condition, but which requires some interpretive thought by the operator.)

a light used to announce a malfunction in a system, especially in a automobile

The green coloured indicator on a motorcycle. Which informs the rider, they are in the "Neutral" gear, when lit.

Lights on the dashboard of a car indicating an action must be taken for continual operation of the vehicle; most commonly the low gas light.

A derisive term for warning lights in a car dashboard or any similar arrangement in a vehicle's cockpit. So called because they light up when the operator is being an idiot and letting something go wrong.

When you have a stick shift car and the little light on the dash comes on. Idiot light

On a moving vehicle, an unused turn signal.