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What is the point of daytime running lights?

Morning traffic on Bay St. near Front St. West in downtown Toronto. (2012 file photo)

Fred Lum/The Globe and Mail

You recently suggested that rear daytime running lights (DRLs) are not mandatory because of energy use, then acknowledged that with the growing use of LEDs, this justification is disappearing. Why does energy use matter at all? Most cars get their electrical power from alternators, so as long as the engine is running, electricity is being generated. I get frustrated seeing so many cars on the road at night with only daytime lights on. Why not have all lights on as soon as the engine starts and off as soon as it turns off? No confusion, fewer light bulbs, easier for manufacturer, simple and safe. – Glen

I could not agree with you more. The excuse about energy use is one bandied about by car companies on occasion. Electricity is indeed being generated while the engine is running – but only as much as required. If the lights are on, there is an additional draw, which requires minute amounts of extra power to drive the alternator. As long as DRLs are wired so that it is possible to drive at night with no tail lights, it's a serious safety issue.

Alarming problem

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I have a 2007 Toyota Camry XLE and its alarm goes off on its own. Two different Toyota shops say that this is strange. One said it would have to keep the vehicle until it actually happened again. The other says that it would start by looking at the access points, without a guarantee of success. I would like to explore other options before spending money on an electronic goose chase. Suggestions? – Sylvia

A technician's worst nightmare – an intermittent electrical fault. The answer lies in the kilometres of wiring and thousands of contact points and somewhere in there, two pieces are making or losing contact. Is it because of changes in ambient temperature or humidity? Vibration? The solution is somewhere between simple and complex – between minutes and hours of searching.

Gas guzzler

I just bought a 1999 Mitsubishi space wagon GDI. The engine was converted as the mechanic said the engine that comes with it is problematic. The new engine emitted black smoke but that has been fixed. However, the car guzzles fuel – on average, using 25 litres/90 km. What can I do. – Yekini

Buy shares in an oil company! Not sure what you mean by converted, I suspect you mean replaced. There was nothing out of the ordinary with the original engine and obviously something terribly wrong with the replacement. I would seek a second opinion. The black cloud would have been the first hint that something is wrong with the air/fuel mixture. The proper ratio of air to fuel in a gasoline engine is in the range of 15:1. Something is way off in your fuel management system so that more fuel than needed is being injected. The fix could be as simple as a setting that enriches the mixture for cold starts that is not being reset as the engine warms up.

Wrong oil type

I just discovered that the business that has been changing my oil has not been using synthetic oil, which my car requires. I have a 2009 Cadillac SRX4. What do I need to look for in damage if any? – Don

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The major advantage of synthetic oils is that they offer improved protection at extreme temperatures. They flow more readily at low temperatures and retain their viscosity at high ones. If the oil changes are being done within the recommended intervals, you should be okay. But, be warned, this may have voided your warranty.

If you have questions about driving or car maintenance, please contact our experts at globedrive@globeandmail.com.

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