auto maintenance February 02, 2018

Idiot Lights: The little lights that usually cry wolf

Idiot light: A warning indicator on the instrument cluster that foretells a failure that never occurs or, conversely, blinks on just after the vehicle has coasted to a stop.

Automotive instrumentation used to be fairly simple. Besides the necessary speedometer, there was a gas gauge (very important), a temperature gauge, and perhaps an oil pressure gauge and a charging meter. Sometime in the 1960s, for reasons I don’t understand, the red engine light indicating low oil pressure or overheating made its appearance. Once they started putting lights on, they couldn’t stop. My ‘68 Chrysler Town & Country wagon had a light to inform me when the engine was cold (duh!).

Fast forward to the late 1990s. A young man brought in his fairly new Oldsmobile to the shop with only 13,000 miles on it. It runs rough, he complained. The first thing I noticed was a “low tire” light on. That was a new one. The car sure did ride rough. A quick check revealed about 75 psi in all the tires when they only needed 30. I asked the man if by chance he had been adding air to the tires, trying to get the light to turn off. He had.

After I corrected his tire pressure it took a good 15 minutes of reading and tinkering to get the light out. The procedure involved opening the fuse panel which was located on the left door side of the dashboard, pushing a reset button while watching the instrument cluster, and waiting for the low tire light to start blinking. After the oil change light starts blinking, and holding the reset for five blinks, maybe it will reset. Try doing this on models where the fuse panel is located on the passenger side of the dash. One person can’t do it: you can’t hit the button and watch the dash — you need 2 people to do it. No wonder so many cars come in with that light on. America is already full of DVD players that blink continuously because people can’t or won’t set them. Let’s stop turning dashboards into DVD players.

A few other examples. Chrysler products used to have a “maintenance required” light that required removal of the instrument cluster to turn off. Jeeps of the same years required the purchase of a $125 module (really just a mechanical hour counter) to turn off the maintenance light. An ancient Volvo came in recently requiring instrument cluster removal to turn out the maintenance light. In spite of the technician’s extreme caution, the brittle plastic circuit board developed a hairline crack. Fortunately, with skill and patience it was repaired, but that’s a little much to turn off an oil change reminder light. I’m beginning to sympathize with the people who use black tape to cover them!

And then there are the lights no one can figure out. I recall someone who replaced the alternator on a Merkur Scorpio because a red warning light was on. It was actually a low brake pad indicator, but it wasn’t that obvious.

There is a point here. If you clutter up the instrumentation with unnecessary warning lights, or warning lights that are difficult to understand or reset, people will simply ignore them, perhaps with serious consequences. I know some of these warning lights are federally mandated, such as the tire pressure warning system. So please try to make them easy to understand and reset. Remember “kiss” for “keep it simple, stupid.”

I was recently in a Toyota Sienna van with a low tire pressure light on. After I set the pressure in the tires, I pushed the clearly marked low tire reset button. This mechanic says “Thank you, Toyota.” For years Honda had a lovely maintenance (oil change) reminder. A simple mechanical counter that goes from green to yellow to red. Once the service is performed, inserting the ignition key into a slot resets the reminder. Wonderful.

Detroit isn’t alone in its love of warning lights. The European manufacturers Volvo, BMW, and Mercedes Benz love to put on maintenance lights that require a special tool costing hundreds of dollars to reset. And they like to change the circuitry yearly so the ‘97 tool won’t work in ‘98.

The trouble is when it takes our time, it costs you money.

Car owners don’t want to spend their afternoons curled up with their owners’ manual, and neither do we.

We, owners and mechanics, all just want to know what we need to know, when we need to know it, and what steps to take to correct the problem.

Keep it simple, please.

Sign Up for Our Newsletter

Keep up to date with coupons and promotions


Get exclusive access to them all when you sign up for our newsletter.

Ezytire Toolbox