#Lanewatch

I don’t know who coined the term — I suspect it was Car and Driver, which was then at an all-time peak of editorial excellence — but this is probably one of those cases where success has many fathers, and the child in this case was the phrase “idiot light.”

Let’s say that you were a new-car buyer in 1977. The vast majority of the cars you saw in a dealership would have just two gauges: speedometer and fuel level. Any other information was conveyed in binary fashion by a set of light-up warnings. The typical Seventies American car would have TEMP (for overheating), OIL (for lack of oil pressure), ALT (alternator/battery), and BRAKE (for low brake fluid), but some models had additional lights for low coolant and other functions.

The self-appointed automotive cognoscenti were very contemptuous of these lights, because they didn’t convey much information and they usually didn’t convey it until things had gotten drastic. Why not have a temperature gauge to let you know that your car was getting hot on the way up the Grapevine? Or an oil-pressure gauge, to give you a general idea of your engine health? Why couldn’t the driver be trusted to know the real information and to act accordingly?