A century ago, vehicles provided little warning of impending mechanical disaster.

The first thing likely to make a pioneer motorist aware of an overheating problem was a geyser of steam from the radiator, if the engine hadn't already seized solid.

A failure of the lubrication system was often heralded by loud knocks which, if ignored, were often followed by a bang and the appearance of a connecting rod or two from a newly created hole in the crankcase.

Things suddenly getting very dark on a nighttime trip unequivocally delivered the message the electrical system had failed (or the acetylene run out), although a dimming of the lights may have provided some warning.

The dashboards of today's vehicles by comparison provide a veritable galaxy of warning lights designed to send timely messages to motorists that things are possibly going awry. Some are gentle, even somewhat ambiguous, hints that something might need a bit of maintenance down the road, while others convey a more urgent message.

Sorting out which is which is obviously important to your safety and your vehicle's health.

The first basic warning devices were temperature, oil pressure and fuel gauges, an ammeter to let you know what the electrical charging system was up to and perhaps a tachometer to tell you how fast the engine was running so you wouldn't exceed its safe maximum.

The problem with these was that the driver had to actually read them from time to time. The attention deficit issue was solved with the arrival of the "idiot" light, as knowledgeable and responsible, gauge-reading motorists called warning lights. The first to appear was a red light to simply remind you the ignition was switched on so you wouldn't forget and flatten the battery.

Today's instrument cluster can contain a dozen or more warning lights or icons. Not all warning lights in all vehicles may operate quite as described here, and there may be additional warnings not mentioned -- so read your owners manual.

When you first turn on the ignition, all the warning icons usually illuminate for a moment or two as systems (such as the airbags) self-check, then go out if things are normal.

If you notice a light that usually comes on at this time doesn't, have your service technician check it out. The bulb may have failed.

Some simple ones first:

The low fuel light is obvious and means you'd better get some more soon. It varies from make to make, but I wouldn't push my luck for more than 25 km or so, although most vehicles will go further than this. The seat-belt reminder, door ajar and low washer fluid icons are obvious, as is the cruise control symbol, which lets you know this system is available.

If your vehicle has a traction control system, an icon will normally flash to let you know it is doing its thing. And will remain lit as a reminder if you've switched it off. The anti-theft alarm light in some vehicles may flash for a few seconds as the system resets itself.

The "check engine soon" light's message might seem ominous but actually isn't something to get into a panic about. It's hooked up to your vehicle's on-board electronic diagnostic system, which monitors emission, engine and transmission systems. It comes on to indicate a problem, but not usually one that means you have to stop driving. You do need to get it checked out as soon as possible though.

There are a number of warning lights you definitely don't want to ignore.

The engine temperature light (sometimes accompanied by a warning chime) lets you know your engine's coolant is approaching critical temperature. Most vehicles still have a temperature gauge and if the needle is anywhere in the "normal" range things are okay. If it sneaks up into the red or "H" zone, or when the light comes on, the drill is to pull over immediately to avoid serious engine damage.

If there are no streams of water, billows of steam or other obvious signs of distress you can let the vehicle idle, with the air conditioner turned off, for a few minutes to see if the needle will drop back into the normal range. Raising the hood (slowly in case of steam or hot water) may help the engine cool down. If it doesn't, switch off and seek assistance.

Another warning icon (also sometimes accompanied by an audio warning) that you ignore at your fiscal peril is the oil pressure warning light. Lubricating oil is fed to various components in the engine under pressure and if this system quits, it doesn't take long for unlubricated bearings and the like to fail catastrophically.

Stop the vehicle as promptly as it is safe to do so. A few vehicles have an oil level warning light or gauge, but using that old, low-tech dipstick regularly, particularly with a higher-mileage vehicle, is always a good idea.

The brake system warning light is another scary one. All modern vehicles have dual braking systems that pretty much ensure your vehicle will retain a portion of its braking ability in the event of a hydraulic failure, but the light means the system is seriously compromised.

You can drive the vehicle, cautiously, because it won't stop as effectively, to a service shop. If the light flashes while cornering, it could mean a leak has resulted in the brake fluid level becoming low. Get it checked.

Many vehicles (soon to be all) are equipped with a tire-pressure monitoring system. If this warning signal appears, it means the tire has lost air pressure and is possibly even going flat.

Slow down as soon as it is safe to do so. A tire with low air pressure will built up heat rapidly at highway speeds, which will lead to failure. Get to an air pump and check for leaks before continuing.

If the charging system warning light appears it means the system that generates electricity to recharge the battery or the battery itself is malfunctioning. Switch off unnecessary equipment that uses electricity and get to a service centre.

The engine will run off battery power alone for a while, but it won't for long.