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lou's garage

Changing a headlight bulb is a challenge in its own right, but contributes to the need to change light bulbs?Fred Lum/The Globe and Mail

Unlike light bulbs in most homes that last for years, the automotive equivalent can be a real pain. And don’t get me started on how to replace the bulb some vehicles require the human arm to bend in ways it just wasn’t designed to. But for today, let’s discuss why a vehicle may have chronic, repeated bulb failures.

Vibrations: Out of balance tires or bent wheels will result in a noticeable vibration at highway speeds, as do warped brake rotors when braking. If you can feel it in the steering wheel or the seat of your pants, the filaments in the bulbs are also shaking. These constant vibrations will shorten bulb life dramatically.

Electrical system: An alternator that isn’t working at peak efficiency typically results in lower system voltage. However, this is not always the case. Sometimes, the reverse can happen and the voltage may spike randomly, which is detrimental to bulb life. As a battery is nearing the end of its life, the alternator must work harder and longer continually charging it. When this is happening, voltage is higher. It may be within normal operating range, bulb life may be shortened.

Condensation: We have all seen headlights fogged with moisture, which doesn’t mix well with bulb longevity. While it may be entirely feasible to live with lamp assemblies that have visible signs of condensation, expect the bulbs to have issues.

Electrical connectors: When the same bulb repeatedly fails, look specifically at the wiring harness connected to that bulb. You will likely find a corroded and overheated electrical connector. Current will be higher in this situation and the bulb will run hotter, shortening its life.

Touching the bulb during installation: We have all been told don’t touch the bulb bare handed when installing. The truth is some bulbs are sensitive to this and some are not. Just keep in mind that the oil from your skin may cause a hot spot, leading to failure on bulbs that normally run hot.

Cold Weather: Not such a big deal anymore, but still worth mentioning. Sitting outside overnight in frigid Canadian winters and then suddenly heating rapidly will affect bulb longevity when compared to warmer climates.

Aftermarket, brighter bulbs: No one looks at the lifespan statistics for these bulbs, they only see a possible solution to their underperforming headlights. Most of these performance bulbs have a shorter expected lifespan. While they may provide a solution to your one problem, you may be surprised at how often they need replacement.

One final note on aftermarket (HID) High Intensity Discharge bulbs. These are the blue lights that seem much brighter and come commonly equipped on European vehicles. These bulbs are filled with Xenon gas and are sometimes referred to as Xenon light bulbs. They do indeed offer superior lighting and if you can pay more for the original equipment lighting package when you buy the vehicle new, I believe this is a good investment. However, the aftermarket retrofit kits that convert your standard lighting system to HID are rarely a good long-term idea. We regularly service vehicles with these modified headlight systems that have problems because of poor quality flea market bought pieces coupled with shoddy installation, often requiring us to remove the system and revert the vehicle back to stock.


Your automotive questions answered

Love your column, Lou. The excessive oil consumption issue on the Acura MDX was a common problem in the 3.7-litre Acura V6 engine. Acura picked up the cost of repair for my 2012 TL under their seven-year extended warranty, with new rings and pistons.

Geoff H.

Thanks Geoff,

With today’s engines that use low-friction piston rings and forced induction components such as turbochargers, oil consumption is now common. It is so common now in fact that most manufacturers consider some oil consumption to be normal.

As with any manufacturer warranty and/or warranty extensions such as on your Acura, there are a few things to keep in mind. Most importantly is service history for the vehicle. Even if you purchased the vehicle used, any manufacturer will expect to see the full service history when initiating a large dollar warranty claim. This includes the time period before your ownership. When buying used vehicles, chasing down the previous owner’s service history has become far more important.

Secondly, tuning a vehicle - which is an aftermarket modification of the software in order for the engine to produce more power - will void all current and future driveline-related warranty events. Even if you have the software returned to normal before going in for a warranty repair, most manufacturers can now detect both present and past software modifications. Be aware when considering this modification as well as when you are buying a used vehicle.


I have a 2017 Chevrolet Impala. I hit something on the side of the steering wheel where the cruise control is. I kept pushing the buttons and saw something that said manual. I don’t really know what I pushed, but now my speedometer is saying I’m going faster than what I am. How can I fix this?

Vonda P.

I am going to make two assumptions. No. 1 is that you are writing to me from south of the border. No. 2 is that when you kept pushing buttons you accidently changed your speedometer’s units to metric and your vehicle is now reading in kilometres. If you look closely at the bottom of the speedometer gauge you will likely see it now reads km/h instead of MPH. The remainder of the speedometer appears exactly the same making this subtle change easy to miss. Your owner’s manual will detail the buttons to press and procedure of switching it back to miles.

Lou Trottier is owner-operator of All About Imports in Mississauga. Have a question about maintenance and repair? E-mail globedrive@globeandmail.com, placing “Lou’s Garage” in the subject line.

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