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Idiots, Lights and Gauges

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Charles Renny
Modern vehicles have some interesting ways of getting you, the driver, information about what is going on around you. My latest sojourn into the entertaining realm we call vehicle instrumentation dynamics was with a Chevrolet Sonic. When I first looked at the instrument cluster, I saw a shape slightly larger, but very similar to my first satellite radio kit.

The basics were all there: engine speed, ground speed and the condition of the engine as well as the amount of fuel on board were all presented in digital format. In the past, many manufacturers used a combination of digital and analogue (dials with pointers on them). Usually the digital part was in the speedometer and the analogue part was always the tachometer (engine revs).

2012 Chevrolet Sonic tachometer
2012 Chevrolet Sonic (Photo: Chevrolet)

Even earlier cars displayed less information because a) gauges cost money and b) the driver didn’t need to know what was going on because it would soon be obvious if something did go wrong. There were exceptions, such as in sports cars where all gauges were analogue and there tended to be lots of them. Trucks tended to be the same.

In the beginning, gauges were all operated mechanically. There was a cable for the speedometer that went from the gauge to the transmission and another cable that went from the engine to the tachometer and so on. The strangest setup that I’ve seen was on a 1950 MG TF where the tachometer was driven off the back of the generator (alternators hadn’t been invented yet). Standardization eventually put the speedometer front and centre, usually sharing centre stage with the tachometer. On the periphery are the fuel level indicator and engine temperature gauges, although I see the temp gauge is now in danger of becoming a light as well.

These warning indicator lights were originally called idiot lights because real drivers always paid close attention to the gauge to spot something going wrong. Only idiots ignored the gauges and carried on. The name stuck, but today these lights tell us something is wrong and often can indicate how important the problem is.

Volkswagen is the first company that I remember taking lighting to new heights. VW used blue light for night time instrumentation when everyone else was using red. Yellow was used for problems that should be attended to, but weren’t critical. A good example is the check-engine light that comes on when you leave the gas cap loose. Red was reserved for important issues and it came on in a glaring manner so that it couldn’t be ignored.

Which system is better? The older systems were the best of their times. Today there isn’t a mechanical link between the engine and the instrument cluster; it’s all wires. The information provided is still the same and the electronic senders are more accurate, faster and certainly require less maintenance, so I vote for the modern systems. If you don’t like today’s instruments, become a car collector and you can go back to any era you want, including a time before instruments.
Charles Renny
Charles Renny
Automotive expert
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